xref: /linux/arch/x86/Kconfig (revision 720c857907530e6cdc86c9bc1102ea6b372fbfb6)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select GENERIC_VDSO_32
18	select HAVE_DEBUG_STACKOVERFLOW
19	select KMAP_LOCAL
20	select MODULES_USE_ELF_REL
21	select OLD_SIGACTION
22	select ARCH_SPLIT_ARG64
23
24config X86_64
25	def_bool y
26	depends on 64BIT
27	# Options that are inherently 64-bit kernel only:
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_SUPPORTS_PER_VMA_LOCK
31	select HAVE_ARCH_SOFT_DIRTY
32	select MODULES_USE_ELF_RELA
33	select NEED_DMA_MAP_STATE
34	select SWIOTLB
35	select ARCH_HAS_ELFCORE_COMPAT
36	select ZONE_DMA32
37
38config FORCE_DYNAMIC_FTRACE
39	def_bool y
40	depends on X86_32
41	depends on FUNCTION_TRACER
42	select DYNAMIC_FTRACE
43	help
44	  We keep the static function tracing (!DYNAMIC_FTRACE) around
45	  in order to test the non static function tracing in the
46	  generic code, as other architectures still use it. But we
47	  only need to keep it around for x86_64. No need to keep it
48	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
49#
50# Arch settings
51#
52# ( Note that options that are marked 'if X86_64' could in principle be
53#   ported to 32-bit as well. )
54#
55config X86
56	def_bool y
57	#
58	# Note: keep this list sorted alphabetically
59	#
60	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
61	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
62	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
63	select ARCH_32BIT_OFF_T			if X86_32
64	select ARCH_CLOCKSOURCE_INIT
65	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
66	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
67	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
68	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
69	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
70	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
71	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
72	select ARCH_HAS_CACHE_LINE_SIZE
73	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
74	select ARCH_HAS_CPU_FINALIZE_INIT
75	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
76	select ARCH_HAS_CURRENT_STACK_POINTER
77	select ARCH_HAS_DEBUG_VIRTUAL
78	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
79	select ARCH_HAS_DEVMEM_IS_ALLOWED
80	select ARCH_HAS_EARLY_DEBUG		if KGDB
81	select ARCH_HAS_ELF_RANDOMIZE
82	select ARCH_HAS_FAST_MULTIPLIER
83	select ARCH_HAS_FORTIFY_SOURCE
84	select ARCH_HAS_GCOV_PROFILE_ALL
85	select ARCH_HAS_KCOV			if X86_64
86	select ARCH_HAS_MEM_ENCRYPT
87	select ARCH_HAS_MEMBARRIER_SYNC_CORE
88	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
89	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
90	select ARCH_HAS_PMEM_API		if X86_64
91	select ARCH_HAS_PTE_DEVMAP		if X86_64
92	select ARCH_HAS_PTE_SPECIAL
93	select ARCH_HAS_HW_PTE_YOUNG
94	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
95	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
96	select ARCH_HAS_COPY_MC			if X86_64
97	select ARCH_HAS_SET_MEMORY
98	select ARCH_HAS_SET_DIRECT_MAP
99	select ARCH_HAS_STRICT_KERNEL_RWX
100	select ARCH_HAS_STRICT_MODULE_RWX
101	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
102	select ARCH_HAS_SYSCALL_WRAPPER
103	select ARCH_HAS_UBSAN_SANITIZE_ALL
104	select ARCH_HAS_DEBUG_WX
105	select ARCH_HAS_ZONE_DMA_SET if EXPERT
106	select ARCH_HAVE_NMI_SAFE_CMPXCHG
107	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
108	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
109	select ARCH_MIGHT_HAVE_PC_PARPORT
110	select ARCH_MIGHT_HAVE_PC_SERIO
111	select ARCH_STACKWALK
112	select ARCH_SUPPORTS_ACPI
113	select ARCH_SUPPORTS_ATOMIC_RMW
114	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
115	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
116	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
117	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
118	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
119	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
120	select ARCH_SUPPORTS_LTO_CLANG
121	select ARCH_SUPPORTS_LTO_CLANG_THIN
122	select ARCH_USE_BUILTIN_BSWAP
123	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CMPXCHG64
124	select ARCH_USE_MEMTEST
125	select ARCH_USE_QUEUED_RWLOCKS
126	select ARCH_USE_QUEUED_SPINLOCKS
127	select ARCH_USE_SYM_ANNOTATIONS
128	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
129	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
130	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
131	select ARCH_WANTS_NO_INSTR
132	select ARCH_WANT_GENERAL_HUGETLB
133	select ARCH_WANT_HUGE_PMD_SHARE
134	select ARCH_WANT_LD_ORPHAN_WARN
135	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
136	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
137	select ARCH_WANTS_THP_SWAP		if X86_64
138	select ARCH_HAS_PARANOID_L1D_FLUSH
139	select BUILDTIME_TABLE_SORT
140	select CLKEVT_I8253
141	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
142	select CLOCKSOURCE_WATCHDOG
143	# Word-size accesses may read uninitialized data past the trailing \0
144	# in strings and cause false KMSAN reports.
145	select DCACHE_WORD_ACCESS		if !KMSAN
146	select DYNAMIC_SIGFRAME
147	select EDAC_ATOMIC_SCRUB
148	select EDAC_SUPPORT
149	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
150	select GENERIC_CLOCKEVENTS_MIN_ADJUST
151	select GENERIC_CMOS_UPDATE
152	select GENERIC_CPU_AUTOPROBE
153	select GENERIC_CPU_DEVICES
154	select GENERIC_CPU_VULNERABILITIES
155	select GENERIC_EARLY_IOREMAP
156	select GENERIC_ENTRY
157	select GENERIC_IOMAP
158	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
159	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
160	select GENERIC_IRQ_MIGRATION		if SMP
161	select GENERIC_IRQ_PROBE
162	select GENERIC_IRQ_RESERVATION_MODE
163	select GENERIC_IRQ_SHOW
164	select GENERIC_PENDING_IRQ		if SMP
165	select GENERIC_PTDUMP
166	select GENERIC_SMP_IDLE_THREAD
167	select GENERIC_TIME_VSYSCALL
168	select GENERIC_GETTIMEOFDAY
169	select GENERIC_VDSO_TIME_NS
170	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
171	select HARDIRQS_SW_RESEND
172	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
173	select HAS_IOPORT
174	select HAVE_ACPI_APEI			if ACPI
175	select HAVE_ACPI_APEI_NMI		if ACPI
176	select HAVE_ALIGNED_STRUCT_PAGE
177	select HAVE_ARCH_AUDITSYSCALL
178	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
179	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
180	select HAVE_ARCH_JUMP_LABEL
181	select HAVE_ARCH_JUMP_LABEL_RELATIVE
182	select HAVE_ARCH_KASAN			if X86_64
183	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
184	select HAVE_ARCH_KFENCE
185	select HAVE_ARCH_KMSAN			if X86_64
186	select HAVE_ARCH_KGDB
187	select HAVE_ARCH_MMAP_RND_BITS		if MMU
188	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
189	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
190	select HAVE_ARCH_PREL32_RELOCATIONS
191	select HAVE_ARCH_SECCOMP_FILTER
192	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
193	select HAVE_ARCH_STACKLEAK
194	select HAVE_ARCH_TRACEHOOK
195	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
196	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
197	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
198	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
199	select HAVE_ARCH_VMAP_STACK		if X86_64
200	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
201	select HAVE_ARCH_WITHIN_STACK_FRAMES
202	select HAVE_ASM_MODVERSIONS
203	select HAVE_CMPXCHG_DOUBLE
204	select HAVE_CMPXCHG_LOCAL
205	select HAVE_CONTEXT_TRACKING_USER		if X86_64
206	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
207	select HAVE_C_RECORDMCOUNT
208	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
209	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
210	select HAVE_BUILDTIME_MCOUNT_SORT
211	select HAVE_DEBUG_KMEMLEAK
212	select HAVE_DMA_CONTIGUOUS
213	select HAVE_DYNAMIC_FTRACE
214	select HAVE_DYNAMIC_FTRACE_WITH_REGS
215	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
216	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
217	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
218	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
219	select HAVE_EBPF_JIT
220	select HAVE_EFFICIENT_UNALIGNED_ACCESS
221	select HAVE_EISA
222	select HAVE_EXIT_THREAD
223	select HAVE_FAST_GUP
224	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
225	select HAVE_FTRACE_MCOUNT_RECORD
226	select HAVE_FUNCTION_GRAPH_RETVAL	if HAVE_FUNCTION_GRAPH_TRACER
227	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
228	select HAVE_FUNCTION_TRACER
229	select HAVE_GCC_PLUGINS
230	select HAVE_HW_BREAKPOINT
231	select HAVE_IOREMAP_PROT
232	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
233	select HAVE_IRQ_TIME_ACCOUNTING
234	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
235	select HAVE_KERNEL_BZIP2
236	select HAVE_KERNEL_GZIP
237	select HAVE_KERNEL_LZ4
238	select HAVE_KERNEL_LZMA
239	select HAVE_KERNEL_LZO
240	select HAVE_KERNEL_XZ
241	select HAVE_KERNEL_ZSTD
242	select HAVE_KPROBES
243	select HAVE_KPROBES_ON_FTRACE
244	select HAVE_FUNCTION_ERROR_INJECTION
245	select HAVE_KRETPROBES
246	select HAVE_RETHOOK
247	select HAVE_KVM
248	select HAVE_LIVEPATCH			if X86_64
249	select HAVE_MIXED_BREAKPOINTS_REGS
250	select HAVE_MOD_ARCH_SPECIFIC
251	select HAVE_MOVE_PMD
252	select HAVE_MOVE_PUD
253	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
254	select HAVE_NMI
255	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
256	select HAVE_OBJTOOL			if X86_64
257	select HAVE_OPTPROBES
258	select HAVE_PCSPKR_PLATFORM
259	select HAVE_PERF_EVENTS
260	select HAVE_PERF_EVENTS_NMI
261	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
262	select HAVE_PCI
263	select HAVE_PERF_REGS
264	select HAVE_PERF_USER_STACK_DUMP
265	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
266	select MMU_GATHER_MERGE_VMAS
267	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
268	select HAVE_REGS_AND_STACK_ACCESS_API
269	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
270	select HAVE_FUNCTION_ARG_ACCESS_API
271	select HAVE_SETUP_PER_CPU_AREA
272	select HAVE_SOFTIRQ_ON_OWN_STACK
273	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
274	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
275	select HAVE_STATIC_CALL
276	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
277	select HAVE_PREEMPT_DYNAMIC_CALL
278	select HAVE_RSEQ
279	select HAVE_RUST			if X86_64
280	select HAVE_SYSCALL_TRACEPOINTS
281	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
282	select HAVE_UNSTABLE_SCHED_CLOCK
283	select HAVE_USER_RETURN_NOTIFIER
284	select HAVE_GENERIC_VDSO
285	select HOTPLUG_PARALLEL			if SMP && X86_64
286	select HOTPLUG_SMT			if SMP
287	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
288	select IRQ_FORCED_THREADING
289	select LOCK_MM_AND_FIND_VMA
290	select NEED_PER_CPU_EMBED_FIRST_CHUNK
291	select NEED_PER_CPU_PAGE_FIRST_CHUNK
292	select NEED_SG_DMA_LENGTH
293	select PCI_DOMAINS			if PCI
294	select PCI_LOCKLESS_CONFIG		if PCI
295	select PERF_EVENTS
296	select RTC_LIB
297	select RTC_MC146818_LIB
298	select SPARSE_IRQ
299	select SYSCTL_EXCEPTION_TRACE
300	select THREAD_INFO_IN_TASK
301	select TRACE_IRQFLAGS_SUPPORT
302	select TRACE_IRQFLAGS_NMI_SUPPORT
303	select USER_STACKTRACE_SUPPORT
304	select HAVE_ARCH_KCSAN			if X86_64
305	select PROC_PID_ARCH_STATUS		if PROC_FS
306	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
307	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
308	select FUNCTION_ALIGNMENT_4B
309	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
310	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
311
312config INSTRUCTION_DECODER
313	def_bool y
314	depends on KPROBES || PERF_EVENTS || UPROBES
315
316config OUTPUT_FORMAT
317	string
318	default "elf32-i386" if X86_32
319	default "elf64-x86-64" if X86_64
320
321config LOCKDEP_SUPPORT
322	def_bool y
323
324config STACKTRACE_SUPPORT
325	def_bool y
326
327config MMU
328	def_bool y
329
330config ARCH_MMAP_RND_BITS_MIN
331	default 28 if 64BIT
332	default 8
333
334config ARCH_MMAP_RND_BITS_MAX
335	default 32 if 64BIT
336	default 16
337
338config ARCH_MMAP_RND_COMPAT_BITS_MIN
339	default 8
340
341config ARCH_MMAP_RND_COMPAT_BITS_MAX
342	default 16
343
344config SBUS
345	bool
346
347config GENERIC_ISA_DMA
348	def_bool y
349	depends on ISA_DMA_API
350
351config GENERIC_CSUM
352	bool
353	default y if KMSAN || KASAN
354
355config GENERIC_BUG
356	def_bool y
357	depends on BUG
358	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
359
360config GENERIC_BUG_RELATIVE_POINTERS
361	bool
362
363config ARCH_MAY_HAVE_PC_FDC
364	def_bool y
365	depends on ISA_DMA_API
366
367config GENERIC_CALIBRATE_DELAY
368	def_bool y
369
370config ARCH_HAS_CPU_RELAX
371	def_bool y
372
373config ARCH_HIBERNATION_POSSIBLE
374	def_bool y
375
376config ARCH_SUSPEND_POSSIBLE
377	def_bool y
378
379config AUDIT_ARCH
380	def_bool y if X86_64
381
382config KASAN_SHADOW_OFFSET
383	hex
384	depends on KASAN
385	default 0xdffffc0000000000
386
387config HAVE_INTEL_TXT
388	def_bool y
389	depends on INTEL_IOMMU && ACPI
390
391config X86_64_SMP
392	def_bool y
393	depends on X86_64 && SMP
394
395config ARCH_SUPPORTS_UPROBES
396	def_bool y
397
398config FIX_EARLYCON_MEM
399	def_bool y
400
401config DYNAMIC_PHYSICAL_MASK
402	bool
403
404config PGTABLE_LEVELS
405	int
406	default 5 if X86_5LEVEL
407	default 4 if X86_64
408	default 3 if X86_PAE
409	default 2
410
411config CC_HAS_SANE_STACKPROTECTOR
412	bool
413	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
414	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
415	help
416	  We have to make sure stack protector is unconditionally disabled if
417	  the compiler produces broken code or if it does not let us control
418	  the segment on 32-bit kernels.
419
420menu "Processor type and features"
421
422config SMP
423	bool "Symmetric multi-processing support"
424	help
425	  This enables support for systems with more than one CPU. If you have
426	  a system with only one CPU, say N. If you have a system with more
427	  than one CPU, say Y.
428
429	  If you say N here, the kernel will run on uni- and multiprocessor
430	  machines, but will use only one CPU of a multiprocessor machine. If
431	  you say Y here, the kernel will run on many, but not all,
432	  uniprocessor machines. On a uniprocessor machine, the kernel
433	  will run faster if you say N here.
434
435	  Note that if you say Y here and choose architecture "586" or
436	  "Pentium" under "Processor family", the kernel will not work on 486
437	  architectures. Similarly, multiprocessor kernels for the "PPro"
438	  architecture may not work on all Pentium based boards.
439
440	  People using multiprocessor machines who say Y here should also say
441	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
442	  Management" code will be disabled if you say Y here.
443
444	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
445	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
446	  <http://www.tldp.org/docs.html#howto>.
447
448	  If you don't know what to do here, say N.
449
450config X86_X2APIC
451	bool "Support x2apic"
452	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
453	help
454	  This enables x2apic support on CPUs that have this feature.
455
456	  This allows 32-bit apic IDs (so it can support very large systems),
457	  and accesses the local apic via MSRs not via mmio.
458
459	  Some Intel systems circa 2022 and later are locked into x2APIC mode
460	  and can not fall back to the legacy APIC modes if SGX or TDX are
461	  enabled in the BIOS. They will boot with very reduced functionality
462	  without enabling this option.
463
464	  If you don't know what to do here, say N.
465
466config X86_MPPARSE
467	bool "Enable MPS table" if ACPI
468	default y
469	depends on X86_LOCAL_APIC
470	help
471	  For old smp systems that do not have proper acpi support. Newer systems
472	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
473
474config GOLDFISH
475	def_bool y
476	depends on X86_GOLDFISH
477
478config X86_CPU_RESCTRL
479	bool "x86 CPU resource control support"
480	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
481	select KERNFS
482	select PROC_CPU_RESCTRL		if PROC_FS
483	help
484	  Enable x86 CPU resource control support.
485
486	  Provide support for the allocation and monitoring of system resources
487	  usage by the CPU.
488
489	  Intel calls this Intel Resource Director Technology
490	  (Intel(R) RDT). More information about RDT can be found in the
491	  Intel x86 Architecture Software Developer Manual.
492
493	  AMD calls this AMD Platform Quality of Service (AMD QoS).
494	  More information about AMD QoS can be found in the AMD64 Technology
495	  Platform Quality of Service Extensions manual.
496
497	  Say N if unsure.
498
499config X86_FRED
500	bool "Flexible Return and Event Delivery"
501	depends on X86_64
502	help
503	  When enabled, try to use Flexible Return and Event Delivery
504	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
505	  ring transitions and exception/interrupt handling if the
506	  system supports.
507
508if X86_32
509config X86_BIGSMP
510	bool "Support for big SMP systems with more than 8 CPUs"
511	depends on SMP
512	help
513	  This option is needed for the systems that have more than 8 CPUs.
514
515config X86_EXTENDED_PLATFORM
516	bool "Support for extended (non-PC) x86 platforms"
517	default y
518	help
519	  If you disable this option then the kernel will only support
520	  standard PC platforms. (which covers the vast majority of
521	  systems out there.)
522
523	  If you enable this option then you'll be able to select support
524	  for the following (non-PC) 32 bit x86 platforms:
525		Goldfish (Android emulator)
526		AMD Elan
527		RDC R-321x SoC
528		SGI 320/540 (Visual Workstation)
529		STA2X11-based (e.g. Northville)
530		Moorestown MID devices
531
532	  If you have one of these systems, or if you want to build a
533	  generic distribution kernel, say Y here - otherwise say N.
534endif # X86_32
535
536if X86_64
537config X86_EXTENDED_PLATFORM
538	bool "Support for extended (non-PC) x86 platforms"
539	default y
540	help
541	  If you disable this option then the kernel will only support
542	  standard PC platforms. (which covers the vast majority of
543	  systems out there.)
544
545	  If you enable this option then you'll be able to select support
546	  for the following (non-PC) 64 bit x86 platforms:
547		Numascale NumaChip
548		ScaleMP vSMP
549		SGI Ultraviolet
550
551	  If you have one of these systems, or if you want to build a
552	  generic distribution kernel, say Y here - otherwise say N.
553endif # X86_64
554# This is an alphabetically sorted list of 64 bit extended platforms
555# Please maintain the alphabetic order if and when there are additions
556config X86_NUMACHIP
557	bool "Numascale NumaChip"
558	depends on X86_64
559	depends on X86_EXTENDED_PLATFORM
560	depends on NUMA
561	depends on SMP
562	depends on X86_X2APIC
563	depends on PCI_MMCONFIG
564	help
565	  Adds support for Numascale NumaChip large-SMP systems. Needed to
566	  enable more than ~168 cores.
567	  If you don't have one of these, you should say N here.
568
569config X86_VSMP
570	bool "ScaleMP vSMP"
571	select HYPERVISOR_GUEST
572	select PARAVIRT
573	depends on X86_64 && PCI
574	depends on X86_EXTENDED_PLATFORM
575	depends on SMP
576	help
577	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
578	  supposed to run on these EM64T-based machines.  Only choose this option
579	  if you have one of these machines.
580
581config X86_UV
582	bool "SGI Ultraviolet"
583	depends on X86_64
584	depends on X86_EXTENDED_PLATFORM
585	depends on NUMA
586	depends on EFI
587	depends on KEXEC_CORE
588	depends on X86_X2APIC
589	depends on PCI
590	help
591	  This option is needed in order to support SGI Ultraviolet systems.
592	  If you don't have one of these, you should say N here.
593
594# Following is an alphabetically sorted list of 32 bit extended platforms
595# Please maintain the alphabetic order if and when there are additions
596
597config X86_GOLDFISH
598	bool "Goldfish (Virtual Platform)"
599	depends on X86_EXTENDED_PLATFORM
600	help
601	  Enable support for the Goldfish virtual platform used primarily
602	  for Android development. Unless you are building for the Android
603	  Goldfish emulator say N here.
604
605config X86_INTEL_CE
606	bool "CE4100 TV platform"
607	depends on PCI
608	depends on PCI_GODIRECT
609	depends on X86_IO_APIC
610	depends on X86_32
611	depends on X86_EXTENDED_PLATFORM
612	select X86_REBOOTFIXUPS
613	select OF
614	select OF_EARLY_FLATTREE
615	help
616	  Select for the Intel CE media processor (CE4100) SOC.
617	  This option compiles in support for the CE4100 SOC for settop
618	  boxes and media devices.
619
620config X86_INTEL_MID
621	bool "Intel MID platform support"
622	depends on X86_EXTENDED_PLATFORM
623	depends on X86_PLATFORM_DEVICES
624	depends on PCI
625	depends on X86_64 || (PCI_GOANY && X86_32)
626	depends on X86_IO_APIC
627	select I2C
628	select DW_APB_TIMER
629	select INTEL_SCU_PCI
630	help
631	  Select to build a kernel capable of supporting Intel MID (Mobile
632	  Internet Device) platform systems which do not have the PCI legacy
633	  interfaces. If you are building for a PC class system say N here.
634
635	  Intel MID platforms are based on an Intel processor and chipset which
636	  consume less power than most of the x86 derivatives.
637
638config X86_INTEL_QUARK
639	bool "Intel Quark platform support"
640	depends on X86_32
641	depends on X86_EXTENDED_PLATFORM
642	depends on X86_PLATFORM_DEVICES
643	depends on X86_TSC
644	depends on PCI
645	depends on PCI_GOANY
646	depends on X86_IO_APIC
647	select IOSF_MBI
648	select INTEL_IMR
649	select COMMON_CLK
650	help
651	  Select to include support for Quark X1000 SoC.
652	  Say Y here if you have a Quark based system such as the Arduino
653	  compatible Intel Galileo.
654
655config X86_INTEL_LPSS
656	bool "Intel Low Power Subsystem Support"
657	depends on X86 && ACPI && PCI
658	select COMMON_CLK
659	select PINCTRL
660	select IOSF_MBI
661	help
662	  Select to build support for Intel Low Power Subsystem such as
663	  found on Intel Lynxpoint PCH. Selecting this option enables
664	  things like clock tree (common clock framework) and pincontrol
665	  which are needed by the LPSS peripheral drivers.
666
667config X86_AMD_PLATFORM_DEVICE
668	bool "AMD ACPI2Platform devices support"
669	depends on ACPI
670	select COMMON_CLK
671	select PINCTRL
672	help
673	  Select to interpret AMD specific ACPI device to platform device
674	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
675	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
676	  implemented under PINCTRL subsystem.
677
678config IOSF_MBI
679	tristate "Intel SoC IOSF Sideband support for SoC platforms"
680	depends on PCI
681	help
682	  This option enables sideband register access support for Intel SoC
683	  platforms. On these platforms the IOSF sideband is used in lieu of
684	  MSR's for some register accesses, mostly but not limited to thermal
685	  and power. Drivers may query the availability of this device to
686	  determine if they need the sideband in order to work on these
687	  platforms. The sideband is available on the following SoC products.
688	  This list is not meant to be exclusive.
689	   - BayTrail
690	   - Braswell
691	   - Quark
692
693	  You should say Y if you are running a kernel on one of these SoC's.
694
695config IOSF_MBI_DEBUG
696	bool "Enable IOSF sideband access through debugfs"
697	depends on IOSF_MBI && DEBUG_FS
698	help
699	  Select this option to expose the IOSF sideband access registers (MCR,
700	  MDR, MCRX) through debugfs to write and read register information from
701	  different units on the SoC. This is most useful for obtaining device
702	  state information for debug and analysis. As this is a general access
703	  mechanism, users of this option would have specific knowledge of the
704	  device they want to access.
705
706	  If you don't require the option or are in doubt, say N.
707
708config X86_RDC321X
709	bool "RDC R-321x SoC"
710	depends on X86_32
711	depends on X86_EXTENDED_PLATFORM
712	select M486
713	select X86_REBOOTFIXUPS
714	help
715	  This option is needed for RDC R-321x system-on-chip, also known
716	  as R-8610-(G).
717	  If you don't have one of these chips, you should say N here.
718
719config X86_32_NON_STANDARD
720	bool "Support non-standard 32-bit SMP architectures"
721	depends on X86_32 && SMP
722	depends on X86_EXTENDED_PLATFORM
723	help
724	  This option compiles in the bigsmp and STA2X11 default
725	  subarchitectures.  It is intended for a generic binary
726	  kernel. If you select them all, kernel will probe it one by
727	  one and will fallback to default.
728
729# Alphabetically sorted list of Non standard 32 bit platforms
730
731config X86_SUPPORTS_MEMORY_FAILURE
732	def_bool y
733	# MCE code calls memory_failure():
734	depends on X86_MCE
735	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
736	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
737	depends on X86_64 || !SPARSEMEM
738	select ARCH_SUPPORTS_MEMORY_FAILURE
739
740config STA2X11
741	bool "STA2X11 Companion Chip Support"
742	depends on X86_32_NON_STANDARD && PCI
743	select SWIOTLB
744	select MFD_STA2X11
745	select GPIOLIB
746	help
747	  This adds support for boards based on the STA2X11 IO-Hub,
748	  a.k.a. "ConneXt". The chip is used in place of the standard
749	  PC chipset, so all "standard" peripherals are missing. If this
750	  option is selected the kernel will still be able to boot on
751	  standard PC machines.
752
753config X86_32_IRIS
754	tristate "Eurobraille/Iris poweroff module"
755	depends on X86_32
756	help
757	  The Iris machines from EuroBraille do not have APM or ACPI support
758	  to shut themselves down properly.  A special I/O sequence is
759	  needed to do so, which is what this module does at
760	  kernel shutdown.
761
762	  This is only for Iris machines from EuroBraille.
763
764	  If unused, say N.
765
766config SCHED_OMIT_FRAME_POINTER
767	def_bool y
768	prompt "Single-depth WCHAN output"
769	depends on X86
770	help
771	  Calculate simpler /proc/<PID>/wchan values. If this option
772	  is disabled then wchan values will recurse back to the
773	  caller function. This provides more accurate wchan values,
774	  at the expense of slightly more scheduling overhead.
775
776	  If in doubt, say "Y".
777
778menuconfig HYPERVISOR_GUEST
779	bool "Linux guest support"
780	help
781	  Say Y here to enable options for running Linux under various hyper-
782	  visors. This option enables basic hypervisor detection and platform
783	  setup.
784
785	  If you say N, all options in this submenu will be skipped and
786	  disabled, and Linux guest support won't be built in.
787
788if HYPERVISOR_GUEST
789
790config PARAVIRT
791	bool "Enable paravirtualization code"
792	depends on HAVE_STATIC_CALL
793	help
794	  This changes the kernel so it can modify itself when it is run
795	  under a hypervisor, potentially improving performance significantly
796	  over full virtualization.  However, when run without a hypervisor
797	  the kernel is theoretically slower and slightly larger.
798
799config PARAVIRT_XXL
800	bool
801
802config PARAVIRT_DEBUG
803	bool "paravirt-ops debugging"
804	depends on PARAVIRT && DEBUG_KERNEL
805	help
806	  Enable to debug paravirt_ops internals.  Specifically, BUG if
807	  a paravirt_op is missing when it is called.
808
809config PARAVIRT_SPINLOCKS
810	bool "Paravirtualization layer for spinlocks"
811	depends on PARAVIRT && SMP
812	help
813	  Paravirtualized spinlocks allow a pvops backend to replace the
814	  spinlock implementation with something virtualization-friendly
815	  (for example, block the virtual CPU rather than spinning).
816
817	  It has a minimal impact on native kernels and gives a nice performance
818	  benefit on paravirtualized KVM / Xen kernels.
819
820	  If you are unsure how to answer this question, answer Y.
821
822config X86_HV_CALLBACK_VECTOR
823	def_bool n
824
825source "arch/x86/xen/Kconfig"
826
827config KVM_GUEST
828	bool "KVM Guest support (including kvmclock)"
829	depends on PARAVIRT
830	select PARAVIRT_CLOCK
831	select ARCH_CPUIDLE_HALTPOLL
832	select X86_HV_CALLBACK_VECTOR
833	default y
834	help
835	  This option enables various optimizations for running under the KVM
836	  hypervisor. It includes a paravirtualized clock, so that instead
837	  of relying on a PIT (or probably other) emulation by the
838	  underlying device model, the host provides the guest with
839	  timing infrastructure such as time of day, and system time
840
841config ARCH_CPUIDLE_HALTPOLL
842	def_bool n
843	prompt "Disable host haltpoll when loading haltpoll driver"
844	help
845	  If virtualized under KVM, disable host haltpoll.
846
847config PVH
848	bool "Support for running PVH guests"
849	help
850	  This option enables the PVH entry point for guest virtual machines
851	  as specified in the x86/HVM direct boot ABI.
852
853config PARAVIRT_TIME_ACCOUNTING
854	bool "Paravirtual steal time accounting"
855	depends on PARAVIRT
856	help
857	  Select this option to enable fine granularity task steal time
858	  accounting. Time spent executing other tasks in parallel with
859	  the current vCPU is discounted from the vCPU power. To account for
860	  that, there can be a small performance impact.
861
862	  If in doubt, say N here.
863
864config PARAVIRT_CLOCK
865	bool
866
867config JAILHOUSE_GUEST
868	bool "Jailhouse non-root cell support"
869	depends on X86_64 && PCI
870	select X86_PM_TIMER
871	help
872	  This option allows to run Linux as guest in a Jailhouse non-root
873	  cell. You can leave this option disabled if you only want to start
874	  Jailhouse and run Linux afterwards in the root cell.
875
876config ACRN_GUEST
877	bool "ACRN Guest support"
878	depends on X86_64
879	select X86_HV_CALLBACK_VECTOR
880	help
881	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
882	  a flexible, lightweight reference open-source hypervisor, built with
883	  real-time and safety-criticality in mind. It is built for embedded
884	  IOT with small footprint and real-time features. More details can be
885	  found in https://projectacrn.org/.
886
887config INTEL_TDX_GUEST
888	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
889	depends on X86_64 && CPU_SUP_INTEL
890	depends on X86_X2APIC
891	depends on EFI_STUB
892	select ARCH_HAS_CC_PLATFORM
893	select X86_MEM_ENCRYPT
894	select X86_MCE
895	select UNACCEPTED_MEMORY
896	help
897	  Support running as a guest under Intel TDX.  Without this support,
898	  the guest kernel can not boot or run under TDX.
899	  TDX includes memory encryption and integrity capabilities
900	  which protect the confidentiality and integrity of guest
901	  memory contents and CPU state. TDX guests are protected from
902	  some attacks from the VMM.
903
904endif # HYPERVISOR_GUEST
905
906source "arch/x86/Kconfig.cpu"
907
908config HPET_TIMER
909	def_bool X86_64
910	prompt "HPET Timer Support" if X86_32
911	help
912	  Use the IA-PC HPET (High Precision Event Timer) to manage
913	  time in preference to the PIT and RTC, if a HPET is
914	  present.
915	  HPET is the next generation timer replacing legacy 8254s.
916	  The HPET provides a stable time base on SMP
917	  systems, unlike the TSC, but it is more expensive to access,
918	  as it is off-chip.  The interface used is documented
919	  in the HPET spec, revision 1.
920
921	  You can safely choose Y here.  However, HPET will only be
922	  activated if the platform and the BIOS support this feature.
923	  Otherwise the 8254 will be used for timing services.
924
925	  Choose N to continue using the legacy 8254 timer.
926
927config HPET_EMULATE_RTC
928	def_bool y
929	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
930
931# Mark as expert because too many people got it wrong.
932# The code disables itself when not needed.
933config DMI
934	default y
935	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
936	bool "Enable DMI scanning" if EXPERT
937	help
938	  Enabled scanning of DMI to identify machine quirks. Say Y
939	  here unless you have verified that your setup is not
940	  affected by entries in the DMI blacklist. Required by PNP
941	  BIOS code.
942
943config GART_IOMMU
944	bool "Old AMD GART IOMMU support"
945	select DMA_OPS
946	select IOMMU_HELPER
947	select SWIOTLB
948	depends on X86_64 && PCI && AMD_NB
949	help
950	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
951	  GART based hardware IOMMUs.
952
953	  The GART supports full DMA access for devices with 32-bit access
954	  limitations, on systems with more than 3 GB. This is usually needed
955	  for USB, sound, many IDE/SATA chipsets and some other devices.
956
957	  Newer systems typically have a modern AMD IOMMU, supported via
958	  the CONFIG_AMD_IOMMU=y config option.
959
960	  In normal configurations this driver is only active when needed:
961	  there's more than 3 GB of memory and the system contains a
962	  32-bit limited device.
963
964	  If unsure, say Y.
965
966config BOOT_VESA_SUPPORT
967	bool
968	help
969	  If true, at least one selected framebuffer driver can take advantage
970	  of VESA video modes set at an early boot stage via the vga= parameter.
971
972config MAXSMP
973	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
974	depends on X86_64 && SMP && DEBUG_KERNEL
975	select CPUMASK_OFFSTACK
976	help
977	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
978	  If unsure, say N.
979
980#
981# The maximum number of CPUs supported:
982#
983# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
984# and which can be configured interactively in the
985# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
986#
987# The ranges are different on 32-bit and 64-bit kernels, depending on
988# hardware capabilities and scalability features of the kernel.
989#
990# ( If MAXSMP is enabled we just use the highest possible value and disable
991#   interactive configuration. )
992#
993
994config NR_CPUS_RANGE_BEGIN
995	int
996	default NR_CPUS_RANGE_END if MAXSMP
997	default    1 if !SMP
998	default    2
999
1000config NR_CPUS_RANGE_END
1001	int
1002	depends on X86_32
1003	default   64 if  SMP &&  X86_BIGSMP
1004	default    8 if  SMP && !X86_BIGSMP
1005	default    1 if !SMP
1006
1007config NR_CPUS_RANGE_END
1008	int
1009	depends on X86_64
1010	default 8192 if  SMP && CPUMASK_OFFSTACK
1011	default  512 if  SMP && !CPUMASK_OFFSTACK
1012	default    1 if !SMP
1013
1014config NR_CPUS_DEFAULT
1015	int
1016	depends on X86_32
1017	default   32 if  X86_BIGSMP
1018	default    8 if  SMP
1019	default    1 if !SMP
1020
1021config NR_CPUS_DEFAULT
1022	int
1023	depends on X86_64
1024	default 8192 if  MAXSMP
1025	default   64 if  SMP
1026	default    1 if !SMP
1027
1028config NR_CPUS
1029	int "Maximum number of CPUs" if SMP && !MAXSMP
1030	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1031	default NR_CPUS_DEFAULT
1032	help
1033	  This allows you to specify the maximum number of CPUs which this
1034	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1035	  supported value is 8192, otherwise the maximum value is 512.  The
1036	  minimum value which makes sense is 2.
1037
1038	  This is purely to save memory: each supported CPU adds about 8KB
1039	  to the kernel image.
1040
1041config SCHED_CLUSTER
1042	bool "Cluster scheduler support"
1043	depends on SMP
1044	default y
1045	help
1046	  Cluster scheduler support improves the CPU scheduler's decision
1047	  making when dealing with machines that have clusters of CPUs.
1048	  Cluster usually means a couple of CPUs which are placed closely
1049	  by sharing mid-level caches, last-level cache tags or internal
1050	  busses.
1051
1052config SCHED_SMT
1053	def_bool y if SMP
1054
1055config SCHED_MC
1056	def_bool y
1057	prompt "Multi-core scheduler support"
1058	depends on SMP
1059	help
1060	  Multi-core scheduler support improves the CPU scheduler's decision
1061	  making when dealing with multi-core CPU chips at a cost of slightly
1062	  increased overhead in some places. If unsure say N here.
1063
1064config SCHED_MC_PRIO
1065	bool "CPU core priorities scheduler support"
1066	depends on SCHED_MC && CPU_SUP_INTEL
1067	select X86_INTEL_PSTATE
1068	select CPU_FREQ
1069	default y
1070	help
1071	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1072	  core ordering determined at manufacturing time, which allows
1073	  certain cores to reach higher turbo frequencies (when running
1074	  single threaded workloads) than others.
1075
1076	  Enabling this kernel feature teaches the scheduler about
1077	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1078	  scheduler's CPU selection logic accordingly, so that higher
1079	  overall system performance can be achieved.
1080
1081	  This feature will have no effect on CPUs without this feature.
1082
1083	  If unsure say Y here.
1084
1085config UP_LATE_INIT
1086	def_bool y
1087	depends on !SMP && X86_LOCAL_APIC
1088
1089config X86_UP_APIC
1090	bool "Local APIC support on uniprocessors" if !PCI_MSI
1091	default PCI_MSI
1092	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1093	help
1094	  A local APIC (Advanced Programmable Interrupt Controller) is an
1095	  integrated interrupt controller in the CPU. If you have a single-CPU
1096	  system which has a processor with a local APIC, you can say Y here to
1097	  enable and use it. If you say Y here even though your machine doesn't
1098	  have a local APIC, then the kernel will still run with no slowdown at
1099	  all. The local APIC supports CPU-generated self-interrupts (timer,
1100	  performance counters), and the NMI watchdog which detects hard
1101	  lockups.
1102
1103config X86_UP_IOAPIC
1104	bool "IO-APIC support on uniprocessors"
1105	depends on X86_UP_APIC
1106	help
1107	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1108	  SMP-capable replacement for PC-style interrupt controllers. Most
1109	  SMP systems and many recent uniprocessor systems have one.
1110
1111	  If you have a single-CPU system with an IO-APIC, you can say Y here
1112	  to use it. If you say Y here even though your machine doesn't have
1113	  an IO-APIC, then the kernel will still run with no slowdown at all.
1114
1115config X86_LOCAL_APIC
1116	def_bool y
1117	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1118	select IRQ_DOMAIN_HIERARCHY
1119
1120config X86_IO_APIC
1121	def_bool y
1122	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1123
1124config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1125	bool "Reroute for broken boot IRQs"
1126	depends on X86_IO_APIC
1127	help
1128	  This option enables a workaround that fixes a source of
1129	  spurious interrupts. This is recommended when threaded
1130	  interrupt handling is used on systems where the generation of
1131	  superfluous "boot interrupts" cannot be disabled.
1132
1133	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1134	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1135	  kernel does during interrupt handling). On chipsets where this
1136	  boot IRQ generation cannot be disabled, this workaround keeps
1137	  the original IRQ line masked so that only the equivalent "boot
1138	  IRQ" is delivered to the CPUs. The workaround also tells the
1139	  kernel to set up the IRQ handler on the boot IRQ line. In this
1140	  way only one interrupt is delivered to the kernel. Otherwise
1141	  the spurious second interrupt may cause the kernel to bring
1142	  down (vital) interrupt lines.
1143
1144	  Only affects "broken" chipsets. Interrupt sharing may be
1145	  increased on these systems.
1146
1147config X86_MCE
1148	bool "Machine Check / overheating reporting"
1149	select GENERIC_ALLOCATOR
1150	default y
1151	help
1152	  Machine Check support allows the processor to notify the
1153	  kernel if it detects a problem (e.g. overheating, data corruption).
1154	  The action the kernel takes depends on the severity of the problem,
1155	  ranging from warning messages to halting the machine.
1156
1157config X86_MCELOG_LEGACY
1158	bool "Support for deprecated /dev/mcelog character device"
1159	depends on X86_MCE
1160	help
1161	  Enable support for /dev/mcelog which is needed by the old mcelog
1162	  userspace logging daemon. Consider switching to the new generation
1163	  rasdaemon solution.
1164
1165config X86_MCE_INTEL
1166	def_bool y
1167	prompt "Intel MCE features"
1168	depends on X86_MCE && X86_LOCAL_APIC
1169	help
1170	  Additional support for intel specific MCE features such as
1171	  the thermal monitor.
1172
1173config X86_MCE_AMD
1174	def_bool y
1175	prompt "AMD MCE features"
1176	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1177	help
1178	  Additional support for AMD specific MCE features such as
1179	  the DRAM Error Threshold.
1180
1181config X86_ANCIENT_MCE
1182	bool "Support for old Pentium 5 / WinChip machine checks"
1183	depends on X86_32 && X86_MCE
1184	help
1185	  Include support for machine check handling on old Pentium 5 or WinChip
1186	  systems. These typically need to be enabled explicitly on the command
1187	  line.
1188
1189config X86_MCE_THRESHOLD
1190	depends on X86_MCE_AMD || X86_MCE_INTEL
1191	def_bool y
1192
1193config X86_MCE_INJECT
1194	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1195	tristate "Machine check injector support"
1196	help
1197	  Provide support for injecting machine checks for testing purposes.
1198	  If you don't know what a machine check is and you don't do kernel
1199	  QA it is safe to say n.
1200
1201source "arch/x86/events/Kconfig"
1202
1203config X86_LEGACY_VM86
1204	bool "Legacy VM86 support"
1205	depends on X86_32
1206	help
1207	  This option allows user programs to put the CPU into V8086
1208	  mode, which is an 80286-era approximation of 16-bit real mode.
1209
1210	  Some very old versions of X and/or vbetool require this option
1211	  for user mode setting.  Similarly, DOSEMU will use it if
1212	  available to accelerate real mode DOS programs.  However, any
1213	  recent version of DOSEMU, X, or vbetool should be fully
1214	  functional even without kernel VM86 support, as they will all
1215	  fall back to software emulation. Nevertheless, if you are using
1216	  a 16-bit DOS program where 16-bit performance matters, vm86
1217	  mode might be faster than emulation and you might want to
1218	  enable this option.
1219
1220	  Note that any app that works on a 64-bit kernel is unlikely to
1221	  need this option, as 64-bit kernels don't, and can't, support
1222	  V8086 mode. This option is also unrelated to 16-bit protected
1223	  mode and is not needed to run most 16-bit programs under Wine.
1224
1225	  Enabling this option increases the complexity of the kernel
1226	  and slows down exception handling a tiny bit.
1227
1228	  If unsure, say N here.
1229
1230config VM86
1231	bool
1232	default X86_LEGACY_VM86
1233
1234config X86_16BIT
1235	bool "Enable support for 16-bit segments" if EXPERT
1236	default y
1237	depends on MODIFY_LDT_SYSCALL
1238	help
1239	  This option is required by programs like Wine to run 16-bit
1240	  protected mode legacy code on x86 processors.  Disabling
1241	  this option saves about 300 bytes on i386, or around 6K text
1242	  plus 16K runtime memory on x86-64,
1243
1244config X86_ESPFIX32
1245	def_bool y
1246	depends on X86_16BIT && X86_32
1247
1248config X86_ESPFIX64
1249	def_bool y
1250	depends on X86_16BIT && X86_64
1251
1252config X86_VSYSCALL_EMULATION
1253	bool "Enable vsyscall emulation" if EXPERT
1254	default y
1255	depends on X86_64
1256	help
1257	  This enables emulation of the legacy vsyscall page.  Disabling
1258	  it is roughly equivalent to booting with vsyscall=none, except
1259	  that it will also disable the helpful warning if a program
1260	  tries to use a vsyscall.  With this option set to N, offending
1261	  programs will just segfault, citing addresses of the form
1262	  0xffffffffff600?00.
1263
1264	  This option is required by many programs built before 2013, and
1265	  care should be used even with newer programs if set to N.
1266
1267	  Disabling this option saves about 7K of kernel size and
1268	  possibly 4K of additional runtime pagetable memory.
1269
1270config X86_IOPL_IOPERM
1271	bool "IOPERM and IOPL Emulation"
1272	default y
1273	help
1274	  This enables the ioperm() and iopl() syscalls which are necessary
1275	  for legacy applications.
1276
1277	  Legacy IOPL support is an overbroad mechanism which allows user
1278	  space aside of accessing all 65536 I/O ports also to disable
1279	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1280	  capabilities and permission from potentially active security
1281	  modules.
1282
1283	  The emulation restricts the functionality of the syscall to
1284	  only allowing the full range I/O port access, but prevents the
1285	  ability to disable interrupts from user space which would be
1286	  granted if the hardware IOPL mechanism would be used.
1287
1288config TOSHIBA
1289	tristate "Toshiba Laptop support"
1290	depends on X86_32
1291	help
1292	  This adds a driver to safely access the System Management Mode of
1293	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1294	  not work on models with a Phoenix BIOS. The System Management Mode
1295	  is used to set the BIOS and power saving options on Toshiba portables.
1296
1297	  For information on utilities to make use of this driver see the
1298	  Toshiba Linux utilities web site at:
1299	  <http://www.buzzard.org.uk/toshiba/>.
1300
1301	  Say Y if you intend to run this kernel on a Toshiba portable.
1302	  Say N otherwise.
1303
1304config X86_REBOOTFIXUPS
1305	bool "Enable X86 board specific fixups for reboot"
1306	depends on X86_32
1307	help
1308	  This enables chipset and/or board specific fixups to be done
1309	  in order to get reboot to work correctly. This is only needed on
1310	  some combinations of hardware and BIOS. The symptom, for which
1311	  this config is intended, is when reboot ends with a stalled/hung
1312	  system.
1313
1314	  Currently, the only fixup is for the Geode machines using
1315	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1316
1317	  Say Y if you want to enable the fixup. Currently, it's safe to
1318	  enable this option even if you don't need it.
1319	  Say N otherwise.
1320
1321config MICROCODE
1322	def_bool y
1323	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1324
1325config MICROCODE_INITRD32
1326	def_bool y
1327	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1328
1329config MICROCODE_LATE_LOADING
1330	bool "Late microcode loading (DANGEROUS)"
1331	default n
1332	depends on MICROCODE && SMP
1333	help
1334	  Loading microcode late, when the system is up and executing instructions
1335	  is a tricky business and should be avoided if possible. Just the sequence
1336	  of synchronizing all cores and SMT threads is one fragile dance which does
1337	  not guarantee that cores might not softlock after the loading. Therefore,
1338	  use this at your own risk. Late loading taints the kernel unless the
1339	  microcode header indicates that it is safe for late loading via the
1340	  minimal revision check. This minimal revision check can be enforced on
1341	  the kernel command line with "microcode.minrev=Y".
1342
1343config MICROCODE_LATE_FORCE_MINREV
1344	bool "Enforce late microcode loading minimal revision check"
1345	default n
1346	depends on MICROCODE_LATE_LOADING
1347	help
1348	  To prevent that users load microcode late which modifies already
1349	  in use features, newer microcode patches have a minimum revision field
1350	  in the microcode header, which tells the kernel which minimum
1351	  revision must be active in the CPU to safely load that new microcode
1352	  late into the running system. If disabled the check will not
1353	  be enforced but the kernel will be tainted when the minimal
1354	  revision check fails.
1355
1356	  This minimal revision check can also be controlled via the
1357	  "microcode.minrev" parameter on the kernel command line.
1358
1359	  If unsure say Y.
1360
1361config X86_MSR
1362	tristate "/dev/cpu/*/msr - Model-specific register support"
1363	help
1364	  This device gives privileged processes access to the x86
1365	  Model-Specific Registers (MSRs).  It is a character device with
1366	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1367	  MSR accesses are directed to a specific CPU on multi-processor
1368	  systems.
1369
1370config X86_CPUID
1371	tristate "/dev/cpu/*/cpuid - CPU information support"
1372	help
1373	  This device gives processes access to the x86 CPUID instruction to
1374	  be executed on a specific processor.  It is a character device
1375	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1376	  /dev/cpu/31/cpuid.
1377
1378choice
1379	prompt "High Memory Support"
1380	default HIGHMEM4G
1381	depends on X86_32
1382
1383config NOHIGHMEM
1384	bool "off"
1385	help
1386	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1387	  However, the address space of 32-bit x86 processors is only 4
1388	  Gigabytes large. That means that, if you have a large amount of
1389	  physical memory, not all of it can be "permanently mapped" by the
1390	  kernel. The physical memory that's not permanently mapped is called
1391	  "high memory".
1392
1393	  If you are compiling a kernel which will never run on a machine with
1394	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1395	  choice and suitable for most users). This will result in a "3GB/1GB"
1396	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1397	  space and the remaining part of the 4GB virtual memory space is used
1398	  by the kernel to permanently map as much physical memory as
1399	  possible.
1400
1401	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1402	  answer "4GB" here.
1403
1404	  If more than 4 Gigabytes is used then answer "64GB" here. This
1405	  selection turns Intel PAE (Physical Address Extension) mode on.
1406	  PAE implements 3-level paging on IA32 processors. PAE is fully
1407	  supported by Linux, PAE mode is implemented on all recent Intel
1408	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1409	  then the kernel will not boot on CPUs that don't support PAE!
1410
1411	  The actual amount of total physical memory will either be
1412	  auto detected or can be forced by using a kernel command line option
1413	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1414	  your boot loader (lilo or loadlin) about how to pass options to the
1415	  kernel at boot time.)
1416
1417	  If unsure, say "off".
1418
1419config HIGHMEM4G
1420	bool "4GB"
1421	help
1422	  Select this if you have a 32-bit processor and between 1 and 4
1423	  gigabytes of physical RAM.
1424
1425config HIGHMEM64G
1426	bool "64GB"
1427	depends on X86_HAVE_PAE
1428	select X86_PAE
1429	help
1430	  Select this if you have a 32-bit processor and more than 4
1431	  gigabytes of physical RAM.
1432
1433endchoice
1434
1435choice
1436	prompt "Memory split" if EXPERT
1437	default VMSPLIT_3G
1438	depends on X86_32
1439	help
1440	  Select the desired split between kernel and user memory.
1441
1442	  If the address range available to the kernel is less than the
1443	  physical memory installed, the remaining memory will be available
1444	  as "high memory". Accessing high memory is a little more costly
1445	  than low memory, as it needs to be mapped into the kernel first.
1446	  Note that increasing the kernel address space limits the range
1447	  available to user programs, making the address space there
1448	  tighter.  Selecting anything other than the default 3G/1G split
1449	  will also likely make your kernel incompatible with binary-only
1450	  kernel modules.
1451
1452	  If you are not absolutely sure what you are doing, leave this
1453	  option alone!
1454
1455	config VMSPLIT_3G
1456		bool "3G/1G user/kernel split"
1457	config VMSPLIT_3G_OPT
1458		depends on !X86_PAE
1459		bool "3G/1G user/kernel split (for full 1G low memory)"
1460	config VMSPLIT_2G
1461		bool "2G/2G user/kernel split"
1462	config VMSPLIT_2G_OPT
1463		depends on !X86_PAE
1464		bool "2G/2G user/kernel split (for full 2G low memory)"
1465	config VMSPLIT_1G
1466		bool "1G/3G user/kernel split"
1467endchoice
1468
1469config PAGE_OFFSET
1470	hex
1471	default 0xB0000000 if VMSPLIT_3G_OPT
1472	default 0x80000000 if VMSPLIT_2G
1473	default 0x78000000 if VMSPLIT_2G_OPT
1474	default 0x40000000 if VMSPLIT_1G
1475	default 0xC0000000
1476	depends on X86_32
1477
1478config HIGHMEM
1479	def_bool y
1480	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1481
1482config X86_PAE
1483	bool "PAE (Physical Address Extension) Support"
1484	depends on X86_32 && X86_HAVE_PAE
1485	select PHYS_ADDR_T_64BIT
1486	select SWIOTLB
1487	help
1488	  PAE is required for NX support, and furthermore enables
1489	  larger swapspace support for non-overcommit purposes. It
1490	  has the cost of more pagetable lookup overhead, and also
1491	  consumes more pagetable space per process.
1492
1493config X86_5LEVEL
1494	bool "Enable 5-level page tables support"
1495	default y
1496	select DYNAMIC_MEMORY_LAYOUT
1497	select SPARSEMEM_VMEMMAP
1498	depends on X86_64
1499	help
1500	  5-level paging enables access to larger address space:
1501	  up to 128 PiB of virtual address space and 4 PiB of
1502	  physical address space.
1503
1504	  It will be supported by future Intel CPUs.
1505
1506	  A kernel with the option enabled can be booted on machines that
1507	  support 4- or 5-level paging.
1508
1509	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1510	  information.
1511
1512	  Say N if unsure.
1513
1514config X86_DIRECT_GBPAGES
1515	def_bool y
1516	depends on X86_64
1517	help
1518	  Certain kernel features effectively disable kernel
1519	  linear 1 GB mappings (even if the CPU otherwise
1520	  supports them), so don't confuse the user by printing
1521	  that we have them enabled.
1522
1523config X86_CPA_STATISTICS
1524	bool "Enable statistic for Change Page Attribute"
1525	depends on DEBUG_FS
1526	help
1527	  Expose statistics about the Change Page Attribute mechanism, which
1528	  helps to determine the effectiveness of preserving large and huge
1529	  page mappings when mapping protections are changed.
1530
1531config X86_MEM_ENCRYPT
1532	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1533	select DYNAMIC_PHYSICAL_MASK
1534	def_bool n
1535
1536config AMD_MEM_ENCRYPT
1537	bool "AMD Secure Memory Encryption (SME) support"
1538	depends on X86_64 && CPU_SUP_AMD
1539	depends on EFI_STUB
1540	select DMA_COHERENT_POOL
1541	select ARCH_USE_MEMREMAP_PROT
1542	select INSTRUCTION_DECODER
1543	select ARCH_HAS_CC_PLATFORM
1544	select X86_MEM_ENCRYPT
1545	select UNACCEPTED_MEMORY
1546	help
1547	  Say yes to enable support for the encryption of system memory.
1548	  This requires an AMD processor that supports Secure Memory
1549	  Encryption (SME).
1550
1551config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1552	bool "Activate AMD Secure Memory Encryption (SME) by default"
1553	depends on AMD_MEM_ENCRYPT
1554	help
1555	  Say yes to have system memory encrypted by default if running on
1556	  an AMD processor that supports Secure Memory Encryption (SME).
1557
1558	  If set to Y, then the encryption of system memory can be
1559	  deactivated with the mem_encrypt=off command line option.
1560
1561	  If set to N, then the encryption of system memory can be
1562	  activated with the mem_encrypt=on command line option.
1563
1564# Common NUMA Features
1565config NUMA
1566	bool "NUMA Memory Allocation and Scheduler Support"
1567	depends on SMP
1568	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1569	default y if X86_BIGSMP
1570	select USE_PERCPU_NUMA_NODE_ID
1571	select OF_NUMA if OF
1572	help
1573	  Enable NUMA (Non-Uniform Memory Access) support.
1574
1575	  The kernel will try to allocate memory used by a CPU on the
1576	  local memory controller of the CPU and add some more
1577	  NUMA awareness to the kernel.
1578
1579	  For 64-bit this is recommended if the system is Intel Core i7
1580	  (or later), AMD Opteron, or EM64T NUMA.
1581
1582	  For 32-bit this is only needed if you boot a 32-bit
1583	  kernel on a 64-bit NUMA platform.
1584
1585	  Otherwise, you should say N.
1586
1587config AMD_NUMA
1588	def_bool y
1589	prompt "Old style AMD Opteron NUMA detection"
1590	depends on X86_64 && NUMA && PCI
1591	help
1592	  Enable AMD NUMA node topology detection.  You should say Y here if
1593	  you have a multi processor AMD system. This uses an old method to
1594	  read the NUMA configuration directly from the builtin Northbridge
1595	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1596	  which also takes priority if both are compiled in.
1597
1598config X86_64_ACPI_NUMA
1599	def_bool y
1600	prompt "ACPI NUMA detection"
1601	depends on X86_64 && NUMA && ACPI && PCI
1602	select ACPI_NUMA
1603	help
1604	  Enable ACPI SRAT based node topology detection.
1605
1606config NUMA_EMU
1607	bool "NUMA emulation"
1608	depends on NUMA
1609	help
1610	  Enable NUMA emulation. A flat machine will be split
1611	  into virtual nodes when booted with "numa=fake=N", where N is the
1612	  number of nodes. This is only useful for debugging.
1613
1614config NODES_SHIFT
1615	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1616	range 1 10
1617	default "10" if MAXSMP
1618	default "6" if X86_64
1619	default "3"
1620	depends on NUMA
1621	help
1622	  Specify the maximum number of NUMA Nodes available on the target
1623	  system.  Increases memory reserved to accommodate various tables.
1624
1625config ARCH_FLATMEM_ENABLE
1626	def_bool y
1627	depends on X86_32 && !NUMA
1628
1629config ARCH_SPARSEMEM_ENABLE
1630	def_bool y
1631	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1632	select SPARSEMEM_STATIC if X86_32
1633	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1634
1635config ARCH_SPARSEMEM_DEFAULT
1636	def_bool X86_64 || (NUMA && X86_32)
1637
1638config ARCH_SELECT_MEMORY_MODEL
1639	def_bool y
1640	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1641
1642config ARCH_MEMORY_PROBE
1643	bool "Enable sysfs memory/probe interface"
1644	depends on MEMORY_HOTPLUG
1645	help
1646	  This option enables a sysfs memory/probe interface for testing.
1647	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1648	  If you are unsure how to answer this question, answer N.
1649
1650config ARCH_PROC_KCORE_TEXT
1651	def_bool y
1652	depends on X86_64 && PROC_KCORE
1653
1654config ILLEGAL_POINTER_VALUE
1655	hex
1656	default 0 if X86_32
1657	default 0xdead000000000000 if X86_64
1658
1659config X86_PMEM_LEGACY_DEVICE
1660	bool
1661
1662config X86_PMEM_LEGACY
1663	tristate "Support non-standard NVDIMMs and ADR protected memory"
1664	depends on PHYS_ADDR_T_64BIT
1665	depends on BLK_DEV
1666	select X86_PMEM_LEGACY_DEVICE
1667	select NUMA_KEEP_MEMINFO if NUMA
1668	select LIBNVDIMM
1669	help
1670	  Treat memory marked using the non-standard e820 type of 12 as used
1671	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1672	  The kernel will offer these regions to the 'pmem' driver so
1673	  they can be used for persistent storage.
1674
1675	  Say Y if unsure.
1676
1677config HIGHPTE
1678	bool "Allocate 3rd-level pagetables from highmem"
1679	depends on HIGHMEM
1680	help
1681	  The VM uses one page table entry for each page of physical memory.
1682	  For systems with a lot of RAM, this can be wasteful of precious
1683	  low memory.  Setting this option will put user-space page table
1684	  entries in high memory.
1685
1686config X86_CHECK_BIOS_CORRUPTION
1687	bool "Check for low memory corruption"
1688	help
1689	  Periodically check for memory corruption in low memory, which
1690	  is suspected to be caused by BIOS.  Even when enabled in the
1691	  configuration, it is disabled at runtime.  Enable it by
1692	  setting "memory_corruption_check=1" on the kernel command
1693	  line.  By default it scans the low 64k of memory every 60
1694	  seconds; see the memory_corruption_check_size and
1695	  memory_corruption_check_period parameters in
1696	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1697
1698	  When enabled with the default parameters, this option has
1699	  almost no overhead, as it reserves a relatively small amount
1700	  of memory and scans it infrequently.  It both detects corruption
1701	  and prevents it from affecting the running system.
1702
1703	  It is, however, intended as a diagnostic tool; if repeatable
1704	  BIOS-originated corruption always affects the same memory,
1705	  you can use memmap= to prevent the kernel from using that
1706	  memory.
1707
1708config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1709	bool "Set the default setting of memory_corruption_check"
1710	depends on X86_CHECK_BIOS_CORRUPTION
1711	default y
1712	help
1713	  Set whether the default state of memory_corruption_check is
1714	  on or off.
1715
1716config MATH_EMULATION
1717	bool
1718	depends on MODIFY_LDT_SYSCALL
1719	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1720	help
1721	  Linux can emulate a math coprocessor (used for floating point
1722	  operations) if you don't have one. 486DX and Pentium processors have
1723	  a math coprocessor built in, 486SX and 386 do not, unless you added
1724	  a 487DX or 387, respectively. (The messages during boot time can
1725	  give you some hints here ["man dmesg"].) Everyone needs either a
1726	  coprocessor or this emulation.
1727
1728	  If you don't have a math coprocessor, you need to say Y here; if you
1729	  say Y here even though you have a coprocessor, the coprocessor will
1730	  be used nevertheless. (This behavior can be changed with the kernel
1731	  command line option "no387", which comes handy if your coprocessor
1732	  is broken. Try "man bootparam" or see the documentation of your boot
1733	  loader (lilo or loadlin) about how to pass options to the kernel at
1734	  boot time.) This means that it is a good idea to say Y here if you
1735	  intend to use this kernel on different machines.
1736
1737	  More information about the internals of the Linux math coprocessor
1738	  emulation can be found in <file:arch/x86/math-emu/README>.
1739
1740	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1741	  kernel, it won't hurt.
1742
1743config MTRR
1744	def_bool y
1745	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1746	help
1747	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1748	  the Memory Type Range Registers (MTRRs) may be used to control
1749	  processor access to memory ranges. This is most useful if you have
1750	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1751	  allows bus write transfers to be combined into a larger transfer
1752	  before bursting over the PCI/AGP bus. This can increase performance
1753	  of image write operations 2.5 times or more. Saying Y here creates a
1754	  /proc/mtrr file which may be used to manipulate your processor's
1755	  MTRRs. Typically the X server should use this.
1756
1757	  This code has a reasonably generic interface so that similar
1758	  control registers on other processors can be easily supported
1759	  as well:
1760
1761	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1762	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1763	  these, the ARRs are used to emulate the MTRRs.
1764	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1765	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1766	  write-combining. All of these processors are supported by this code
1767	  and it makes sense to say Y here if you have one of them.
1768
1769	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1770	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1771	  can lead to all sorts of problems, so it's good to say Y here.
1772
1773	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1774	  just add about 9 KB to your kernel.
1775
1776	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1777
1778config MTRR_SANITIZER
1779	def_bool y
1780	prompt "MTRR cleanup support"
1781	depends on MTRR
1782	help
1783	  Convert MTRR layout from continuous to discrete, so X drivers can
1784	  add writeback entries.
1785
1786	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1787	  The largest mtrr entry size for a continuous block can be set with
1788	  mtrr_chunk_size.
1789
1790	  If unsure, say Y.
1791
1792config MTRR_SANITIZER_ENABLE_DEFAULT
1793	int "MTRR cleanup enable value (0-1)"
1794	range 0 1
1795	default "0"
1796	depends on MTRR_SANITIZER
1797	help
1798	  Enable mtrr cleanup default value
1799
1800config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1801	int "MTRR cleanup spare reg num (0-7)"
1802	range 0 7
1803	default "1"
1804	depends on MTRR_SANITIZER
1805	help
1806	  mtrr cleanup spare entries default, it can be changed via
1807	  mtrr_spare_reg_nr=N on the kernel command line.
1808
1809config X86_PAT
1810	def_bool y
1811	prompt "x86 PAT support" if EXPERT
1812	depends on MTRR
1813	help
1814	  Use PAT attributes to setup page level cache control.
1815
1816	  PATs are the modern equivalents of MTRRs and are much more
1817	  flexible than MTRRs.
1818
1819	  Say N here if you see bootup problems (boot crash, boot hang,
1820	  spontaneous reboots) or a non-working video driver.
1821
1822	  If unsure, say Y.
1823
1824config ARCH_USES_PG_UNCACHED
1825	def_bool y
1826	depends on X86_PAT
1827
1828config X86_UMIP
1829	def_bool y
1830	prompt "User Mode Instruction Prevention" if EXPERT
1831	help
1832	  User Mode Instruction Prevention (UMIP) is a security feature in
1833	  some x86 processors. If enabled, a general protection fault is
1834	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1835	  executed in user mode. These instructions unnecessarily expose
1836	  information about the hardware state.
1837
1838	  The vast majority of applications do not use these instructions.
1839	  For the very few that do, software emulation is provided in
1840	  specific cases in protected and virtual-8086 modes. Emulated
1841	  results are dummy.
1842
1843config CC_HAS_IBT
1844	# GCC >= 9 and binutils >= 2.29
1845	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1846	# Clang/LLVM >= 14
1847	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1848	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1849	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1850		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1851		  $(as-instr,endbr64)
1852
1853config X86_CET
1854	def_bool n
1855	help
1856	  CET features configured (Shadow stack or IBT)
1857
1858config X86_KERNEL_IBT
1859	prompt "Indirect Branch Tracking"
1860	def_bool y
1861	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1862	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1863	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1864	select OBJTOOL
1865	select X86_CET
1866	help
1867	  Build the kernel with support for Indirect Branch Tracking, a
1868	  hardware support course-grain forward-edge Control Flow Integrity
1869	  protection. It enforces that all indirect calls must land on
1870	  an ENDBR instruction, as such, the compiler will instrument the
1871	  code with them to make this happen.
1872
1873	  In addition to building the kernel with IBT, seal all functions that
1874	  are not indirect call targets, avoiding them ever becoming one.
1875
1876	  This requires LTO like objtool runs and will slow down the build. It
1877	  does significantly reduce the number of ENDBR instructions in the
1878	  kernel image.
1879
1880config X86_INTEL_MEMORY_PROTECTION_KEYS
1881	prompt "Memory Protection Keys"
1882	def_bool y
1883	# Note: only available in 64-bit mode
1884	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1885	select ARCH_USES_HIGH_VMA_FLAGS
1886	select ARCH_HAS_PKEYS
1887	help
1888	  Memory Protection Keys provides a mechanism for enforcing
1889	  page-based protections, but without requiring modification of the
1890	  page tables when an application changes protection domains.
1891
1892	  For details, see Documentation/core-api/protection-keys.rst
1893
1894	  If unsure, say y.
1895
1896choice
1897	prompt "TSX enable mode"
1898	depends on CPU_SUP_INTEL
1899	default X86_INTEL_TSX_MODE_OFF
1900	help
1901	  Intel's TSX (Transactional Synchronization Extensions) feature
1902	  allows to optimize locking protocols through lock elision which
1903	  can lead to a noticeable performance boost.
1904
1905	  On the other hand it has been shown that TSX can be exploited
1906	  to form side channel attacks (e.g. TAA) and chances are there
1907	  will be more of those attacks discovered in the future.
1908
1909	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1910	  might override this decision by tsx=on the command line parameter.
1911	  Even with TSX enabled, the kernel will attempt to enable the best
1912	  possible TAA mitigation setting depending on the microcode available
1913	  for the particular machine.
1914
1915	  This option allows to set the default tsx mode between tsx=on, =off
1916	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1917	  details.
1918
1919	  Say off if not sure, auto if TSX is in use but it should be used on safe
1920	  platforms or on if TSX is in use and the security aspect of tsx is not
1921	  relevant.
1922
1923config X86_INTEL_TSX_MODE_OFF
1924	bool "off"
1925	help
1926	  TSX is disabled if possible - equals to tsx=off command line parameter.
1927
1928config X86_INTEL_TSX_MODE_ON
1929	bool "on"
1930	help
1931	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1932	  line parameter.
1933
1934config X86_INTEL_TSX_MODE_AUTO
1935	bool "auto"
1936	help
1937	  TSX is enabled on TSX capable HW that is believed to be safe against
1938	  side channel attacks- equals the tsx=auto command line parameter.
1939endchoice
1940
1941config X86_SGX
1942	bool "Software Guard eXtensions (SGX)"
1943	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1944	depends on CRYPTO=y
1945	depends on CRYPTO_SHA256=y
1946	select MMU_NOTIFIER
1947	select NUMA_KEEP_MEMINFO if NUMA
1948	select XARRAY_MULTI
1949	help
1950	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1951	  that can be used by applications to set aside private regions of code
1952	  and data, referred to as enclaves. An enclave's private memory can
1953	  only be accessed by code running within the enclave. Accesses from
1954	  outside the enclave, including other enclaves, are disallowed by
1955	  hardware.
1956
1957	  If unsure, say N.
1958
1959config X86_USER_SHADOW_STACK
1960	bool "X86 userspace shadow stack"
1961	depends on AS_WRUSS
1962	depends on X86_64
1963	select ARCH_USES_HIGH_VMA_FLAGS
1964	select X86_CET
1965	help
1966	  Shadow stack protection is a hardware feature that detects function
1967	  return address corruption.  This helps mitigate ROP attacks.
1968	  Applications must be enabled to use it, and old userspace does not
1969	  get protection "for free".
1970
1971	  CPUs supporting shadow stacks were first released in 2020.
1972
1973	  See Documentation/arch/x86/shstk.rst for more information.
1974
1975	  If unsure, say N.
1976
1977config INTEL_TDX_HOST
1978	bool "Intel Trust Domain Extensions (TDX) host support"
1979	depends on CPU_SUP_INTEL
1980	depends on X86_64
1981	depends on KVM_INTEL
1982	depends on X86_X2APIC
1983	select ARCH_KEEP_MEMBLOCK
1984	depends on CONTIG_ALLOC
1985	depends on !KEXEC_CORE
1986	depends on X86_MCE
1987	help
1988	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1989	  host and certain physical attacks.  This option enables necessary TDX
1990	  support in the host kernel to run confidential VMs.
1991
1992	  If unsure, say N.
1993
1994config EFI
1995	bool "EFI runtime service support"
1996	depends on ACPI
1997	select UCS2_STRING
1998	select EFI_RUNTIME_WRAPPERS
1999	select ARCH_USE_MEMREMAP_PROT
2000	select EFI_RUNTIME_MAP if KEXEC_CORE
2001	help
2002	  This enables the kernel to use EFI runtime services that are
2003	  available (such as the EFI variable services).
2004
2005	  This option is only useful on systems that have EFI firmware.
2006	  In addition, you should use the latest ELILO loader available
2007	  at <http://elilo.sourceforge.net> in order to take advantage
2008	  of EFI runtime services. However, even with this option, the
2009	  resultant kernel should continue to boot on existing non-EFI
2010	  platforms.
2011
2012config EFI_STUB
2013	bool "EFI stub support"
2014	depends on EFI
2015	select RELOCATABLE
2016	help
2017	  This kernel feature allows a bzImage to be loaded directly
2018	  by EFI firmware without the use of a bootloader.
2019
2020	  See Documentation/admin-guide/efi-stub.rst for more information.
2021
2022config EFI_HANDOVER_PROTOCOL
2023	bool "EFI handover protocol (DEPRECATED)"
2024	depends on EFI_STUB
2025	default y
2026	help
2027	  Select this in order to include support for the deprecated EFI
2028	  handover protocol, which defines alternative entry points into the
2029	  EFI stub.  This is a practice that has no basis in the UEFI
2030	  specification, and requires a priori knowledge on the part of the
2031	  bootloader about Linux/x86 specific ways of passing the command line
2032	  and initrd, and where in memory those assets may be loaded.
2033
2034	  If in doubt, say Y. Even though the corresponding support is not
2035	  present in upstream GRUB or other bootloaders, most distros build
2036	  GRUB with numerous downstream patches applied, and may rely on the
2037	  handover protocol as as result.
2038
2039config EFI_MIXED
2040	bool "EFI mixed-mode support"
2041	depends on EFI_STUB && X86_64
2042	help
2043	  Enabling this feature allows a 64-bit kernel to be booted
2044	  on a 32-bit firmware, provided that your CPU supports 64-bit
2045	  mode.
2046
2047	  Note that it is not possible to boot a mixed-mode enabled
2048	  kernel via the EFI boot stub - a bootloader that supports
2049	  the EFI handover protocol must be used.
2050
2051	  If unsure, say N.
2052
2053config EFI_FAKE_MEMMAP
2054	bool "Enable EFI fake memory map"
2055	depends on EFI
2056	help
2057	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
2058	  this parameter, you can add arbitrary attribute to specific memory
2059	  range by updating original (firmware provided) EFI memmap.  This is
2060	  useful for debugging of EFI memmap related feature, e.g., Address
2061	  Range Mirroring feature.
2062
2063config EFI_MAX_FAKE_MEM
2064	int "maximum allowable number of ranges in efi_fake_mem boot option"
2065	depends on EFI_FAKE_MEMMAP
2066	range 1 128
2067	default 8
2068	help
2069	  Maximum allowable number of ranges in efi_fake_mem boot option.
2070	  Ranges can be set up to this value using comma-separated list.
2071	  The default value is 8.
2072
2073config EFI_RUNTIME_MAP
2074	bool "Export EFI runtime maps to sysfs" if EXPERT
2075	depends on EFI
2076	help
2077	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2078	  That memory map is required by the 2nd kernel to set up EFI virtual
2079	  mappings after kexec, but can also be used for debugging purposes.
2080
2081	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2082
2083source "kernel/Kconfig.hz"
2084
2085config ARCH_SUPPORTS_KEXEC
2086	def_bool y
2087
2088config ARCH_SUPPORTS_KEXEC_FILE
2089	def_bool X86_64
2090
2091config ARCH_SELECTS_KEXEC_FILE
2092	def_bool y
2093	depends on KEXEC_FILE
2094	select HAVE_IMA_KEXEC if IMA
2095
2096config ARCH_SUPPORTS_KEXEC_PURGATORY
2097	def_bool y
2098
2099config ARCH_SUPPORTS_KEXEC_SIG
2100	def_bool y
2101
2102config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2103	def_bool y
2104
2105config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2106	def_bool y
2107
2108config ARCH_SUPPORTS_KEXEC_JUMP
2109	def_bool y
2110
2111config ARCH_SUPPORTS_CRASH_DUMP
2112	def_bool X86_64 || (X86_32 && HIGHMEM)
2113
2114config ARCH_SUPPORTS_CRASH_HOTPLUG
2115	def_bool y
2116
2117config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2118	def_bool CRASH_CORE
2119
2120config PHYSICAL_START
2121	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2122	default "0x1000000"
2123	help
2124	  This gives the physical address where the kernel is loaded.
2125
2126	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2127	  bzImage will decompress itself to above physical address and
2128	  run from there. Otherwise, bzImage will run from the address where
2129	  it has been loaded by the boot loader and will ignore above physical
2130	  address.
2131
2132	  In normal kdump cases one does not have to set/change this option
2133	  as now bzImage can be compiled as a completely relocatable image
2134	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2135	  address. This option is mainly useful for the folks who don't want
2136	  to use a bzImage for capturing the crash dump and want to use a
2137	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2138	  to be specifically compiled to run from a specific memory area
2139	  (normally a reserved region) and this option comes handy.
2140
2141	  So if you are using bzImage for capturing the crash dump,
2142	  leave the value here unchanged to 0x1000000 and set
2143	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2144	  for capturing the crash dump change this value to start of
2145	  the reserved region.  In other words, it can be set based on
2146	  the "X" value as specified in the "crashkernel=YM@XM"
2147	  command line boot parameter passed to the panic-ed
2148	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2149	  for more details about crash dumps.
2150
2151	  Usage of bzImage for capturing the crash dump is recommended as
2152	  one does not have to build two kernels. Same kernel can be used
2153	  as production kernel and capture kernel. Above option should have
2154	  gone away after relocatable bzImage support is introduced. But it
2155	  is present because there are users out there who continue to use
2156	  vmlinux for dump capture. This option should go away down the
2157	  line.
2158
2159	  Don't change this unless you know what you are doing.
2160
2161config RELOCATABLE
2162	bool "Build a relocatable kernel"
2163	default y
2164	help
2165	  This builds a kernel image that retains relocation information
2166	  so it can be loaded someplace besides the default 1MB.
2167	  The relocations tend to make the kernel binary about 10% larger,
2168	  but are discarded at runtime.
2169
2170	  One use is for the kexec on panic case where the recovery kernel
2171	  must live at a different physical address than the primary
2172	  kernel.
2173
2174	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2175	  it has been loaded at and the compile time physical address
2176	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2177
2178config RANDOMIZE_BASE
2179	bool "Randomize the address of the kernel image (KASLR)"
2180	depends on RELOCATABLE
2181	default y
2182	help
2183	  In support of Kernel Address Space Layout Randomization (KASLR),
2184	  this randomizes the physical address at which the kernel image
2185	  is decompressed and the virtual address where the kernel
2186	  image is mapped, as a security feature that deters exploit
2187	  attempts relying on knowledge of the location of kernel
2188	  code internals.
2189
2190	  On 64-bit, the kernel physical and virtual addresses are
2191	  randomized separately. The physical address will be anywhere
2192	  between 16MB and the top of physical memory (up to 64TB). The
2193	  virtual address will be randomized from 16MB up to 1GB (9 bits
2194	  of entropy). Note that this also reduces the memory space
2195	  available to kernel modules from 1.5GB to 1GB.
2196
2197	  On 32-bit, the kernel physical and virtual addresses are
2198	  randomized together. They will be randomized from 16MB up to
2199	  512MB (8 bits of entropy).
2200
2201	  Entropy is generated using the RDRAND instruction if it is
2202	  supported. If RDTSC is supported, its value is mixed into
2203	  the entropy pool as well. If neither RDRAND nor RDTSC are
2204	  supported, then entropy is read from the i8254 timer. The
2205	  usable entropy is limited by the kernel being built using
2206	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2207	  minimum of 2MB. As a result, only 10 bits of entropy are
2208	  theoretically possible, but the implementations are further
2209	  limited due to memory layouts.
2210
2211	  If unsure, say Y.
2212
2213# Relocation on x86 needs some additional build support
2214config X86_NEED_RELOCS
2215	def_bool y
2216	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2217
2218config PHYSICAL_ALIGN
2219	hex "Alignment value to which kernel should be aligned"
2220	default "0x200000"
2221	range 0x2000 0x1000000 if X86_32
2222	range 0x200000 0x1000000 if X86_64
2223	help
2224	  This value puts the alignment restrictions on physical address
2225	  where kernel is loaded and run from. Kernel is compiled for an
2226	  address which meets above alignment restriction.
2227
2228	  If bootloader loads the kernel at a non-aligned address and
2229	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2230	  address aligned to above value and run from there.
2231
2232	  If bootloader loads the kernel at a non-aligned address and
2233	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2234	  load address and decompress itself to the address it has been
2235	  compiled for and run from there. The address for which kernel is
2236	  compiled already meets above alignment restrictions. Hence the
2237	  end result is that kernel runs from a physical address meeting
2238	  above alignment restrictions.
2239
2240	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2241	  this value must be a multiple of 0x200000.
2242
2243	  Don't change this unless you know what you are doing.
2244
2245config DYNAMIC_MEMORY_LAYOUT
2246	bool
2247	help
2248	  This option makes base addresses of vmalloc and vmemmap as well as
2249	  __PAGE_OFFSET movable during boot.
2250
2251config RANDOMIZE_MEMORY
2252	bool "Randomize the kernel memory sections"
2253	depends on X86_64
2254	depends on RANDOMIZE_BASE
2255	select DYNAMIC_MEMORY_LAYOUT
2256	default RANDOMIZE_BASE
2257	help
2258	  Randomizes the base virtual address of kernel memory sections
2259	  (physical memory mapping, vmalloc & vmemmap). This security feature
2260	  makes exploits relying on predictable memory locations less reliable.
2261
2262	  The order of allocations remains unchanged. Entropy is generated in
2263	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2264	  configuration have in average 30,000 different possible virtual
2265	  addresses for each memory section.
2266
2267	  If unsure, say Y.
2268
2269config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2270	hex "Physical memory mapping padding" if EXPERT
2271	depends on RANDOMIZE_MEMORY
2272	default "0xa" if MEMORY_HOTPLUG
2273	default "0x0"
2274	range 0x1 0x40 if MEMORY_HOTPLUG
2275	range 0x0 0x40
2276	help
2277	  Define the padding in terabytes added to the existing physical
2278	  memory size during kernel memory randomization. It is useful
2279	  for memory hotplug support but reduces the entropy available for
2280	  address randomization.
2281
2282	  If unsure, leave at the default value.
2283
2284config ADDRESS_MASKING
2285	bool "Linear Address Masking support"
2286	depends on X86_64
2287	help
2288	  Linear Address Masking (LAM) modifies the checking that is applied
2289	  to 64-bit linear addresses, allowing software to use of the
2290	  untranslated address bits for metadata.
2291
2292	  The capability can be used for efficient address sanitizers (ASAN)
2293	  implementation and for optimizations in JITs.
2294
2295config HOTPLUG_CPU
2296	def_bool y
2297	depends on SMP
2298
2299config COMPAT_VDSO
2300	def_bool n
2301	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2302	depends on COMPAT_32
2303	help
2304	  Certain buggy versions of glibc will crash if they are
2305	  presented with a 32-bit vDSO that is not mapped at the address
2306	  indicated in its segment table.
2307
2308	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2309	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2310	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2311	  the only released version with the bug, but OpenSUSE 9
2312	  contains a buggy "glibc 2.3.2".
2313
2314	  The symptom of the bug is that everything crashes on startup, saying:
2315	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2316
2317	  Saying Y here changes the default value of the vdso32 boot
2318	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2319	  This works around the glibc bug but hurts performance.
2320
2321	  If unsure, say N: if you are compiling your own kernel, you
2322	  are unlikely to be using a buggy version of glibc.
2323
2324choice
2325	prompt "vsyscall table for legacy applications"
2326	depends on X86_64
2327	default LEGACY_VSYSCALL_XONLY
2328	help
2329	  Legacy user code that does not know how to find the vDSO expects
2330	  to be able to issue three syscalls by calling fixed addresses in
2331	  kernel space. Since this location is not randomized with ASLR,
2332	  it can be used to assist security vulnerability exploitation.
2333
2334	  This setting can be changed at boot time via the kernel command
2335	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2336	  is deprecated and can only be enabled using the kernel command
2337	  line.
2338
2339	  On a system with recent enough glibc (2.14 or newer) and no
2340	  static binaries, you can say None without a performance penalty
2341	  to improve security.
2342
2343	  If unsure, select "Emulate execution only".
2344
2345	config LEGACY_VSYSCALL_XONLY
2346		bool "Emulate execution only"
2347		help
2348		  The kernel traps and emulates calls into the fixed vsyscall
2349		  address mapping and does not allow reads.  This
2350		  configuration is recommended when userspace might use the
2351		  legacy vsyscall area but support for legacy binary
2352		  instrumentation of legacy code is not needed.  It mitigates
2353		  certain uses of the vsyscall area as an ASLR-bypassing
2354		  buffer.
2355
2356	config LEGACY_VSYSCALL_NONE
2357		bool "None"
2358		help
2359		  There will be no vsyscall mapping at all. This will
2360		  eliminate any risk of ASLR bypass due to the vsyscall
2361		  fixed address mapping. Attempts to use the vsyscalls
2362		  will be reported to dmesg, so that either old or
2363		  malicious userspace programs can be identified.
2364
2365endchoice
2366
2367config CMDLINE_BOOL
2368	bool "Built-in kernel command line"
2369	help
2370	  Allow for specifying boot arguments to the kernel at
2371	  build time.  On some systems (e.g. embedded ones), it is
2372	  necessary or convenient to provide some or all of the
2373	  kernel boot arguments with the kernel itself (that is,
2374	  to not rely on the boot loader to provide them.)
2375
2376	  To compile command line arguments into the kernel,
2377	  set this option to 'Y', then fill in the
2378	  boot arguments in CONFIG_CMDLINE.
2379
2380	  Systems with fully functional boot loaders (i.e. non-embedded)
2381	  should leave this option set to 'N'.
2382
2383config CMDLINE
2384	string "Built-in kernel command string"
2385	depends on CMDLINE_BOOL
2386	default ""
2387	help
2388	  Enter arguments here that should be compiled into the kernel
2389	  image and used at boot time.  If the boot loader provides a
2390	  command line at boot time, it is appended to this string to
2391	  form the full kernel command line, when the system boots.
2392
2393	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2394	  change this behavior.
2395
2396	  In most cases, the command line (whether built-in or provided
2397	  by the boot loader) should specify the device for the root
2398	  file system.
2399
2400config CMDLINE_OVERRIDE
2401	bool "Built-in command line overrides boot loader arguments"
2402	depends on CMDLINE_BOOL && CMDLINE != ""
2403	help
2404	  Set this option to 'Y' to have the kernel ignore the boot loader
2405	  command line, and use ONLY the built-in command line.
2406
2407	  This is used to work around broken boot loaders.  This should
2408	  be set to 'N' under normal conditions.
2409
2410config MODIFY_LDT_SYSCALL
2411	bool "Enable the LDT (local descriptor table)" if EXPERT
2412	default y
2413	help
2414	  Linux can allow user programs to install a per-process x86
2415	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2416	  call.  This is required to run 16-bit or segmented code such as
2417	  DOSEMU or some Wine programs.  It is also used by some very old
2418	  threading libraries.
2419
2420	  Enabling this feature adds a small amount of overhead to
2421	  context switches and increases the low-level kernel attack
2422	  surface.  Disabling it removes the modify_ldt(2) system call.
2423
2424	  Saying 'N' here may make sense for embedded or server kernels.
2425
2426config STRICT_SIGALTSTACK_SIZE
2427	bool "Enforce strict size checking for sigaltstack"
2428	depends on DYNAMIC_SIGFRAME
2429	help
2430	  For historical reasons MINSIGSTKSZ is a constant which became
2431	  already too small with AVX512 support. Add a mechanism to
2432	  enforce strict checking of the sigaltstack size against the
2433	  real size of the FPU frame. This option enables the check
2434	  by default. It can also be controlled via the kernel command
2435	  line option 'strict_sas_size' independent of this config
2436	  switch. Enabling it might break existing applications which
2437	  allocate a too small sigaltstack but 'work' because they
2438	  never get a signal delivered.
2439
2440	  Say 'N' unless you want to really enforce this check.
2441
2442source "kernel/livepatch/Kconfig"
2443
2444endmenu
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 && RETPOLINE
2478	select CALL_PADDING
2479
2480config HAVE_CALL_THUNKS
2481	def_bool y
2482	depends on CC_HAS_ENTRY_PADDING && 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 SPECULATION_MITIGATIONS
2493	bool "Mitigations for speculative execution vulnerabilities"
2494	default y
2495	help
2496	  Say Y here to enable options which enable mitigations for
2497	  speculative execution hardware vulnerabilities.
2498
2499	  If you say N, all mitigations will be disabled. You really
2500	  should know what you are doing to say so.
2501
2502if SPECULATION_MITIGATIONS
2503
2504config PAGE_TABLE_ISOLATION
2505	bool "Remove the kernel mapping in user mode"
2506	default y
2507	depends on (X86_64 || X86_PAE)
2508	help
2509	  This feature reduces the number of hardware side channels by
2510	  ensuring that the majority of kernel addresses are not mapped
2511	  into userspace.
2512
2513	  See Documentation/arch/x86/pti.rst for more details.
2514
2515config RETPOLINE
2516	bool "Avoid speculative indirect branches in kernel"
2517	select OBJTOOL if HAVE_OBJTOOL
2518	default y
2519	help
2520	  Compile kernel with the retpoline compiler options to guard against
2521	  kernel-to-user data leaks by avoiding speculative indirect
2522	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2523	  support for full protection. The kernel may run slower.
2524
2525config RETHUNK
2526	bool "Enable return-thunks"
2527	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2528	select OBJTOOL if HAVE_OBJTOOL
2529	default y if X86_64
2530	help
2531	  Compile the kernel with the return-thunks compiler option to guard
2532	  against kernel-to-user data leaks by avoiding return speculation.
2533	  Requires a compiler with -mfunction-return=thunk-extern
2534	  support for full protection. The kernel may run slower.
2535
2536config CPU_UNRET_ENTRY
2537	bool "Enable UNRET on kernel entry"
2538	depends on CPU_SUP_AMD && RETHUNK && X86_64
2539	default y
2540	help
2541	  Compile the kernel with support for the retbleed=unret mitigation.
2542
2543config CALL_DEPTH_TRACKING
2544	bool "Mitigate RSB underflow with call depth tracking"
2545	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2546	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2547	select CALL_THUNKS
2548	default y
2549	help
2550	  Compile the kernel with call depth tracking to mitigate the Intel
2551	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
2552	  mitigation is off by default and needs to be enabled on the
2553	  kernel command line via the retbleed=stuff option. For
2554	  non-affected systems the overhead of this option is marginal as
2555	  the call depth tracking is using run-time generated call thunks
2556	  in a compiler generated padding area and call patching. This
2557	  increases text size by ~5%. For non affected systems this space
2558	  is unused. On affected SKL systems this results in a significant
2559	  performance gain over the IBRS mitigation.
2560
2561config CALL_THUNKS_DEBUG
2562	bool "Enable call thunks and call depth tracking debugging"
2563	depends on CALL_DEPTH_TRACKING
2564	select FUNCTION_ALIGNMENT_32B
2565	default n
2566	help
2567	  Enable call/ret counters for imbalance detection and build in
2568	  a noisy dmesg about callthunks generation and call patching for
2569	  trouble shooting. The debug prints need to be enabled on the
2570	  kernel command line with 'debug-callthunks'.
2571	  Only enable this when you are debugging call thunks as this
2572	  creates a noticeable runtime overhead. If unsure say N.
2573
2574config CPU_IBPB_ENTRY
2575	bool "Enable IBPB on kernel entry"
2576	depends on CPU_SUP_AMD && X86_64
2577	default y
2578	help
2579	  Compile the kernel with support for the retbleed=ibpb mitigation.
2580
2581config CPU_IBRS_ENTRY
2582	bool "Enable IBRS on kernel entry"
2583	depends on CPU_SUP_INTEL && X86_64
2584	default y
2585	help
2586	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2587	  This mitigates both spectre_v2 and retbleed at great cost to
2588	  performance.
2589
2590config CPU_SRSO
2591	bool "Mitigate speculative RAS overflow on AMD"
2592	depends on CPU_SUP_AMD && X86_64 && RETHUNK
2593	default y
2594	help
2595	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2596
2597config SLS
2598	bool "Mitigate Straight-Line-Speculation"
2599	depends on CC_HAS_SLS && X86_64
2600	select OBJTOOL if HAVE_OBJTOOL
2601	default n
2602	help
2603	  Compile the kernel with straight-line-speculation options to guard
2604	  against straight line speculation. The kernel image might be slightly
2605	  larger.
2606
2607config GDS_FORCE_MITIGATION
2608	bool "Force GDS Mitigation"
2609	depends on CPU_SUP_INTEL
2610	default n
2611	help
2612	  Gather Data Sampling (GDS) is a hardware vulnerability which allows
2613	  unprivileged speculative access to data which was previously stored in
2614	  vector registers.
2615
2616	  This option is equivalent to setting gather_data_sampling=force on the
2617	  command line. The microcode mitigation is used if present, otherwise
2618	  AVX is disabled as a mitigation. On affected systems that are missing
2619	  the microcode any userspace code that unconditionally uses AVX will
2620	  break with this option set.
2621
2622	  Setting this option on systems not vulnerable to GDS has no effect.
2623
2624	  If in doubt, say N.
2625
2626endif
2627
2628config ARCH_HAS_ADD_PAGES
2629	def_bool y
2630	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2631
2632menu "Power management and ACPI options"
2633
2634config ARCH_HIBERNATION_HEADER
2635	def_bool y
2636	depends on HIBERNATION
2637
2638source "kernel/power/Kconfig"
2639
2640source "drivers/acpi/Kconfig"
2641
2642config X86_APM_BOOT
2643	def_bool y
2644	depends on APM
2645
2646menuconfig APM
2647	tristate "APM (Advanced Power Management) BIOS support"
2648	depends on X86_32 && PM_SLEEP
2649	help
2650	  APM is a BIOS specification for saving power using several different
2651	  techniques. This is mostly useful for battery powered laptops with
2652	  APM compliant BIOSes. If you say Y here, the system time will be
2653	  reset after a RESUME operation, the /proc/apm device will provide
2654	  battery status information, and user-space programs will receive
2655	  notification of APM "events" (e.g. battery status change).
2656
2657	  If you select "Y" here, you can disable actual use of the APM
2658	  BIOS by passing the "apm=off" option to the kernel at boot time.
2659
2660	  Note that the APM support is almost completely disabled for
2661	  machines with more than one CPU.
2662
2663	  In order to use APM, you will need supporting software. For location
2664	  and more information, read <file:Documentation/power/apm-acpi.rst>
2665	  and the Battery Powered Linux mini-HOWTO, available from
2666	  <http://www.tldp.org/docs.html#howto>.
2667
2668	  This driver does not spin down disk drives (see the hdparm(8)
2669	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2670	  VESA-compliant "green" monitors.
2671
2672	  This driver does not support the TI 4000M TravelMate and the ACER
2673	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2674	  desktop machines also don't have compliant BIOSes, and this driver
2675	  may cause those machines to panic during the boot phase.
2676
2677	  Generally, if you don't have a battery in your machine, there isn't
2678	  much point in using this driver and you should say N. If you get
2679	  random kernel OOPSes or reboots that don't seem to be related to
2680	  anything, try disabling/enabling this option (or disabling/enabling
2681	  APM in your BIOS).
2682
2683	  Some other things you should try when experiencing seemingly random,
2684	  "weird" problems:
2685
2686	  1) make sure that you have enough swap space and that it is
2687	  enabled.
2688	  2) pass the "idle=poll" option to the kernel
2689	  3) switch on floating point emulation in the kernel and pass
2690	  the "no387" option to the kernel
2691	  4) pass the "floppy=nodma" option to the kernel
2692	  5) pass the "mem=4M" option to the kernel (thereby disabling
2693	  all but the first 4 MB of RAM)
2694	  6) make sure that the CPU is not over clocked.
2695	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2696	  8) disable the cache from your BIOS settings
2697	  9) install a fan for the video card or exchange video RAM
2698	  10) install a better fan for the CPU
2699	  11) exchange RAM chips
2700	  12) exchange the motherboard.
2701
2702	  To compile this driver as a module, choose M here: the
2703	  module will be called apm.
2704
2705if APM
2706
2707config APM_IGNORE_USER_SUSPEND
2708	bool "Ignore USER SUSPEND"
2709	help
2710	  This option will ignore USER SUSPEND requests. On machines with a
2711	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2712	  series notebooks, it is necessary to say Y because of a BIOS bug.
2713
2714config APM_DO_ENABLE
2715	bool "Enable PM at boot time"
2716	help
2717	  Enable APM features at boot time. From page 36 of the APM BIOS
2718	  specification: "When disabled, the APM BIOS does not automatically
2719	  power manage devices, enter the Standby State, enter the Suspend
2720	  State, or take power saving steps in response to CPU Idle calls."
2721	  This driver will make CPU Idle calls when Linux is idle (unless this
2722	  feature is turned off -- see "Do CPU IDLE calls", below). This
2723	  should always save battery power, but more complicated APM features
2724	  will be dependent on your BIOS implementation. You may need to turn
2725	  this option off if your computer hangs at boot time when using APM
2726	  support, or if it beeps continuously instead of suspending. Turn
2727	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2728	  T400CDT. This is off by default since most machines do fine without
2729	  this feature.
2730
2731config APM_CPU_IDLE
2732	depends on CPU_IDLE
2733	bool "Make CPU Idle calls when idle"
2734	help
2735	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2736	  On some machines, this can activate improved power savings, such as
2737	  a slowed CPU clock rate, when the machine is idle. These idle calls
2738	  are made after the idle loop has run for some length of time (e.g.,
2739	  333 mS). On some machines, this will cause a hang at boot time or
2740	  whenever the CPU becomes idle. (On machines with more than one CPU,
2741	  this option does nothing.)
2742
2743config APM_DISPLAY_BLANK
2744	bool "Enable console blanking using APM"
2745	help
2746	  Enable console blanking using the APM. Some laptops can use this to
2747	  turn off the LCD backlight when the screen blanker of the Linux
2748	  virtual console blanks the screen. Note that this is only used by
2749	  the virtual console screen blanker, and won't turn off the backlight
2750	  when using the X Window system. This also doesn't have anything to
2751	  do with your VESA-compliant power-saving monitor. Further, this
2752	  option doesn't work for all laptops -- it might not turn off your
2753	  backlight at all, or it might print a lot of errors to the console,
2754	  especially if you are using gpm.
2755
2756config APM_ALLOW_INTS
2757	bool "Allow interrupts during APM BIOS calls"
2758	help
2759	  Normally we disable external interrupts while we are making calls to
2760	  the APM BIOS as a measure to lessen the effects of a badly behaving
2761	  BIOS implementation.  The BIOS should reenable interrupts if it
2762	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2763	  many of the newer IBM Thinkpads.  If you experience hangs when you
2764	  suspend, try setting this to Y.  Otherwise, say N.
2765
2766endif # APM
2767
2768source "drivers/cpufreq/Kconfig"
2769
2770source "drivers/cpuidle/Kconfig"
2771
2772source "drivers/idle/Kconfig"
2773
2774endmenu
2775
2776menu "Bus options (PCI etc.)"
2777
2778choice
2779	prompt "PCI access mode"
2780	depends on X86_32 && PCI
2781	default PCI_GOANY
2782	help
2783	  On PCI systems, the BIOS can be used to detect the PCI devices and
2784	  determine their configuration. However, some old PCI motherboards
2785	  have BIOS bugs and may crash if this is done. Also, some embedded
2786	  PCI-based systems don't have any BIOS at all. Linux can also try to
2787	  detect the PCI hardware directly without using the BIOS.
2788
2789	  With this option, you can specify how Linux should detect the
2790	  PCI devices. If you choose "BIOS", the BIOS will be used,
2791	  if you choose "Direct", the BIOS won't be used, and if you
2792	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2793	  If you choose "Any", the kernel will try MMCONFIG, then the
2794	  direct access method and falls back to the BIOS if that doesn't
2795	  work. If unsure, go with the default, which is "Any".
2796
2797config PCI_GOBIOS
2798	bool "BIOS"
2799
2800config PCI_GOMMCONFIG
2801	bool "MMConfig"
2802
2803config PCI_GODIRECT
2804	bool "Direct"
2805
2806config PCI_GOOLPC
2807	bool "OLPC XO-1"
2808	depends on OLPC
2809
2810config PCI_GOANY
2811	bool "Any"
2812
2813endchoice
2814
2815config PCI_BIOS
2816	def_bool y
2817	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2818
2819# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2820config PCI_DIRECT
2821	def_bool y
2822	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2823
2824config PCI_MMCONFIG
2825	bool "Support mmconfig PCI config space access" if X86_64
2826	default y
2827	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2828	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2829
2830config PCI_OLPC
2831	def_bool y
2832	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2833
2834config PCI_XEN
2835	def_bool y
2836	depends on PCI && XEN
2837
2838config MMCONF_FAM10H
2839	def_bool y
2840	depends on X86_64 && PCI_MMCONFIG && ACPI
2841
2842config PCI_CNB20LE_QUIRK
2843	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2844	depends on PCI
2845	help
2846	  Read the PCI windows out of the CNB20LE host bridge. This allows
2847	  PCI hotplug to work on systems with the CNB20LE chipset which do
2848	  not have ACPI.
2849
2850	  There's no public spec for this chipset, and this functionality
2851	  is known to be incomplete.
2852
2853	  You should say N unless you know you need this.
2854
2855config ISA_BUS
2856	bool "ISA bus support on modern systems" if EXPERT
2857	help
2858	  Expose ISA bus device drivers and options available for selection and
2859	  configuration. Enable this option if your target machine has an ISA
2860	  bus. ISA is an older system, displaced by PCI and newer bus
2861	  architectures -- if your target machine is modern, it probably does
2862	  not have an ISA bus.
2863
2864	  If unsure, say N.
2865
2866# x86_64 have no ISA slots, but can have ISA-style DMA.
2867config ISA_DMA_API
2868	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2869	default y
2870	help
2871	  Enables ISA-style DMA support for devices requiring such controllers.
2872	  If unsure, say Y.
2873
2874if X86_32
2875
2876config ISA
2877	bool "ISA support"
2878	help
2879	  Find out whether you have ISA slots on your motherboard.  ISA is the
2880	  name of a bus system, i.e. the way the CPU talks to the other stuff
2881	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2882	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2883	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2884
2885config SCx200
2886	tristate "NatSemi SCx200 support"
2887	help
2888	  This provides basic support for National Semiconductor's
2889	  (now AMD's) Geode processors.  The driver probes for the
2890	  PCI-IDs of several on-chip devices, so its a good dependency
2891	  for other scx200_* drivers.
2892
2893	  If compiled as a module, the driver is named scx200.
2894
2895config SCx200HR_TIMER
2896	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2897	depends on SCx200
2898	default y
2899	help
2900	  This driver provides a clocksource built upon the on-chip
2901	  27MHz high-resolution timer.  Its also a workaround for
2902	  NSC Geode SC-1100's buggy TSC, which loses time when the
2903	  processor goes idle (as is done by the scheduler).  The
2904	  other workaround is idle=poll boot option.
2905
2906config OLPC
2907	bool "One Laptop Per Child support"
2908	depends on !X86_PAE
2909	select GPIOLIB
2910	select OF
2911	select OF_PROMTREE
2912	select IRQ_DOMAIN
2913	select OLPC_EC
2914	help
2915	  Add support for detecting the unique features of the OLPC
2916	  XO hardware.
2917
2918config OLPC_XO1_PM
2919	bool "OLPC XO-1 Power Management"
2920	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2921	help
2922	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2923
2924config OLPC_XO1_RTC
2925	bool "OLPC XO-1 Real Time Clock"
2926	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2927	help
2928	  Add support for the XO-1 real time clock, which can be used as a
2929	  programmable wakeup source.
2930
2931config OLPC_XO1_SCI
2932	bool "OLPC XO-1 SCI extras"
2933	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2934	depends on INPUT=y
2935	select POWER_SUPPLY
2936	help
2937	  Add support for SCI-based features of the OLPC XO-1 laptop:
2938	   - EC-driven system wakeups
2939	   - Power button
2940	   - Ebook switch
2941	   - Lid switch
2942	   - AC adapter status updates
2943	   - Battery status updates
2944
2945config OLPC_XO15_SCI
2946	bool "OLPC XO-1.5 SCI extras"
2947	depends on OLPC && ACPI
2948	select POWER_SUPPLY
2949	help
2950	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2951	   - EC-driven system wakeups
2952	   - AC adapter status updates
2953	   - Battery status updates
2954
2955config ALIX
2956	bool "PCEngines ALIX System Support (LED setup)"
2957	select GPIOLIB
2958	help
2959	  This option enables system support for the PCEngines ALIX.
2960	  At present this just sets up LEDs for GPIO control on
2961	  ALIX2/3/6 boards.  However, other system specific setup should
2962	  get added here.
2963
2964	  Note: You must still enable the drivers for GPIO and LED support
2965	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2966
2967	  Note: You have to set alix.force=1 for boards with Award BIOS.
2968
2969config NET5501
2970	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2971	select GPIOLIB
2972	help
2973	  This option enables system support for the Soekris Engineering net5501.
2974
2975config GEOS
2976	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2977	select GPIOLIB
2978	depends on DMI
2979	help
2980	  This option enables system support for the Traverse Technologies GEOS.
2981
2982config TS5500
2983	bool "Technologic Systems TS-5500 platform support"
2984	depends on MELAN
2985	select CHECK_SIGNATURE
2986	select NEW_LEDS
2987	select LEDS_CLASS
2988	help
2989	  This option enables system support for the Technologic Systems TS-5500.
2990
2991endif # X86_32
2992
2993config AMD_NB
2994	def_bool y
2995	depends on CPU_SUP_AMD && PCI
2996
2997endmenu
2998
2999menu "Binary Emulations"
3000
3001config IA32_EMULATION
3002	bool "IA32 Emulation"
3003	depends on X86_64
3004	select ARCH_WANT_OLD_COMPAT_IPC
3005	select BINFMT_ELF
3006	select COMPAT_OLD_SIGACTION
3007	help
3008	  Include code to run legacy 32-bit programs under a
3009	  64-bit kernel. You should likely turn this on, unless you're
3010	  100% sure that you don't have any 32-bit programs left.
3011
3012config IA32_EMULATION_DEFAULT_DISABLED
3013	bool "IA32 emulation disabled by default"
3014	default n
3015	depends on IA32_EMULATION
3016	help
3017	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3018	  processes and access to 32-bit syscalls. If unsure, leave it to its
3019	  default value.
3020
3021config X86_X32_ABI
3022	bool "x32 ABI for 64-bit mode"
3023	depends on X86_64
3024	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3025	# compressed debug sections to x86_x32 properly:
3026	# https://github.com/ClangBuiltLinux/linux/issues/514
3027	# https://github.com/ClangBuiltLinux/linux/issues/1141
3028	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3029	help
3030	  Include code to run binaries for the x32 native 32-bit ABI
3031	  for 64-bit processors.  An x32 process gets access to the
3032	  full 64-bit register file and wide data path while leaving
3033	  pointers at 32 bits for smaller memory footprint.
3034
3035config COMPAT_32
3036	def_bool y
3037	depends on IA32_EMULATION || X86_32
3038	select HAVE_UID16
3039	select OLD_SIGSUSPEND3
3040
3041config COMPAT
3042	def_bool y
3043	depends on IA32_EMULATION || X86_X32_ABI
3044
3045config COMPAT_FOR_U64_ALIGNMENT
3046	def_bool y
3047	depends on COMPAT
3048
3049endmenu
3050
3051config HAVE_ATOMIC_IOMAP
3052	def_bool y
3053	depends on X86_32
3054
3055source "arch/x86/kvm/Kconfig"
3056
3057source "arch/x86/Kconfig.assembler"
3058