xref: /openbmc/linux/arch/x86/Kconfig (revision 0f9b4c3ca5fdf3e177266ef994071b1a03f07318)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select GENERIC_VDSO_32
18	select HAVE_DEBUG_STACKOVERFLOW
19	select KMAP_LOCAL
20	select MODULES_USE_ELF_REL
21	select OLD_SIGACTION
22	select ARCH_SPLIT_ARG64
23
24config X86_64
25	def_bool y
26	depends on 64BIT
27	# Options that are inherently 64-bit kernel only:
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_SUPPORTS_PER_VMA_LOCK
31	select ARCH_USE_CMPXCHG_LOCKREF
32	select HAVE_ARCH_SOFT_DIRTY
33	select MODULES_USE_ELF_RELA
34	select NEED_DMA_MAP_STATE
35	select SWIOTLB
36	select ARCH_HAS_ELFCORE_COMPAT
37	select ZONE_DMA32
38
39config FORCE_DYNAMIC_FTRACE
40	def_bool y
41	depends on X86_32
42	depends on FUNCTION_TRACER
43	select DYNAMIC_FTRACE
44	help
45	  We keep the static function tracing (!DYNAMIC_FTRACE) around
46	  in order to test the non static function tracing in the
47	  generic code, as other architectures still use it. But we
48	  only need to keep it around for x86_64. No need to keep it
49	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
50#
51# Arch settings
52#
53# ( Note that options that are marked 'if X86_64' could in principle be
54#   ported to 32-bit as well. )
55#
56config X86
57	def_bool y
58	#
59	# Note: keep this list sorted alphabetically
60	#
61	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
62	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
63	select ARCH_32BIT_OFF_T			if X86_32
64	select ARCH_CLOCKSOURCE_INIT
65	select ARCH_CONFIGURES_CPU_MITIGATIONS
66	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
67	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
68	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
69	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
70	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
71	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
72	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
73	select ARCH_HAS_CACHE_LINE_SIZE
74	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
75	select ARCH_HAS_CPU_FINALIZE_INIT
76	select ARCH_HAS_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_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
94	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
95	select ARCH_HAS_COPY_MC			if X86_64
96	select ARCH_HAS_SET_MEMORY
97	select ARCH_HAS_SET_DIRECT_MAP
98	select ARCH_HAS_STRICT_KERNEL_RWX
99	select ARCH_HAS_STRICT_MODULE_RWX
100	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
101	select ARCH_HAS_SYSCALL_WRAPPER
102	select ARCH_HAS_UBSAN_SANITIZE_ALL
103	select ARCH_HAS_DEBUG_WX
104	select ARCH_HAS_ZONE_DMA_SET if EXPERT
105	select ARCH_HAVE_NMI_SAFE_CMPXCHG
106	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
107	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
108	select ARCH_MIGHT_HAVE_PC_PARPORT
109	select ARCH_MIGHT_HAVE_PC_SERIO
110	select ARCH_STACKWALK
111	select ARCH_SUPPORTS_ACPI
112	select ARCH_SUPPORTS_ATOMIC_RMW
113	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
114	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
115	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
116	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
117	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
118	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
119	select ARCH_SUPPORTS_LTO_CLANG
120	select ARCH_SUPPORTS_LTO_CLANG_THIN
121	select ARCH_USE_BUILTIN_BSWAP
122	select ARCH_USE_MEMTEST
123	select ARCH_USE_QUEUED_RWLOCKS
124	select ARCH_USE_QUEUED_SPINLOCKS
125	select ARCH_USE_SYM_ANNOTATIONS
126	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
127	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
128	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
129	select ARCH_WANTS_NO_INSTR
130	select ARCH_WANT_GENERAL_HUGETLB
131	select ARCH_WANT_HUGE_PMD_SHARE
132	select ARCH_WANT_LD_ORPHAN_WARN
133	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
134	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
135	select ARCH_WANTS_THP_SWAP		if X86_64
136	select ARCH_HAS_PARANOID_L1D_FLUSH
137	select BUILDTIME_TABLE_SORT
138	select CLKEVT_I8253
139	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
140	select CLOCKSOURCE_WATCHDOG
141	# Word-size accesses may read uninitialized data past the trailing \0
142	# in strings and cause false KMSAN reports.
143	select DCACHE_WORD_ACCESS		if !KMSAN
144	select DYNAMIC_SIGFRAME
145	select EDAC_ATOMIC_SCRUB
146	select EDAC_SUPPORT
147	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
148	select GENERIC_CLOCKEVENTS_MIN_ADJUST
149	select GENERIC_CMOS_UPDATE
150	select GENERIC_CPU_AUTOPROBE
151	select GENERIC_CPU_VULNERABILITIES
152	select GENERIC_EARLY_IOREMAP
153	select GENERIC_ENTRY
154	select GENERIC_IOMAP
155	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
156	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
157	select GENERIC_IRQ_MIGRATION		if SMP
158	select GENERIC_IRQ_PROBE
159	select GENERIC_IRQ_RESERVATION_MODE
160	select GENERIC_IRQ_SHOW
161	select GENERIC_PENDING_IRQ		if SMP
162	select GENERIC_PTDUMP
163	select GENERIC_SMP_IDLE_THREAD
164	select GENERIC_TIME_VSYSCALL
165	select GENERIC_GETTIMEOFDAY
166	select GENERIC_VDSO_TIME_NS
167	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
168	select HARDIRQS_SW_RESEND
169	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
170	select HAS_IOPORT
171	select HAVE_ACPI_APEI			if ACPI
172	select HAVE_ACPI_APEI_NMI		if ACPI
173	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
174	select HAVE_ARCH_AUDITSYSCALL
175	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
176	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
177	select HAVE_ARCH_JUMP_LABEL
178	select HAVE_ARCH_JUMP_LABEL_RELATIVE
179	select HAVE_ARCH_KASAN			if X86_64
180	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
181	select HAVE_ARCH_KFENCE
182	select HAVE_ARCH_KMSAN			if X86_64
183	select HAVE_ARCH_KGDB
184	select HAVE_ARCH_MMAP_RND_BITS		if MMU
185	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
186	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
187	select HAVE_ARCH_PREL32_RELOCATIONS
188	select HAVE_ARCH_SECCOMP_FILTER
189	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
190	select HAVE_ARCH_STACKLEAK
191	select HAVE_ARCH_TRACEHOOK
192	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
193	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
194	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
195	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
196	select HAVE_ARCH_VMAP_STACK		if X86_64
197	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
198	select HAVE_ARCH_WITHIN_STACK_FRAMES
199	select HAVE_ASM_MODVERSIONS
200	select HAVE_CMPXCHG_DOUBLE
201	select HAVE_CMPXCHG_LOCAL
202	select HAVE_CONTEXT_TRACKING_USER		if X86_64
203	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
204	select HAVE_C_RECORDMCOUNT
205	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
206	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
207	select HAVE_BUILDTIME_MCOUNT_SORT
208	select HAVE_DEBUG_KMEMLEAK
209	select HAVE_DMA_CONTIGUOUS
210	select HAVE_DYNAMIC_FTRACE
211	select HAVE_DYNAMIC_FTRACE_WITH_REGS
212	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
213	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
214	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
215	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
216	select HAVE_EBPF_JIT
217	select HAVE_EFFICIENT_UNALIGNED_ACCESS
218	select HAVE_EISA
219	select HAVE_EXIT_THREAD
220	select HAVE_FAST_GUP
221	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
222	select HAVE_FTRACE_MCOUNT_RECORD
223	select HAVE_FUNCTION_GRAPH_RETVAL	if HAVE_FUNCTION_GRAPH_TRACER
224	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
225	select HAVE_FUNCTION_TRACER
226	select HAVE_GCC_PLUGINS
227	select HAVE_HW_BREAKPOINT
228	select HAVE_IOREMAP_PROT
229	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
230	select HAVE_IRQ_TIME_ACCOUNTING
231	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
232	select HAVE_KERNEL_BZIP2
233	select HAVE_KERNEL_GZIP
234	select HAVE_KERNEL_LZ4
235	select HAVE_KERNEL_LZMA
236	select HAVE_KERNEL_LZO
237	select HAVE_KERNEL_XZ
238	select HAVE_KERNEL_ZSTD
239	select HAVE_KPROBES
240	select HAVE_KPROBES_ON_FTRACE
241	select HAVE_FUNCTION_ERROR_INJECTION
242	select HAVE_KRETPROBES
243	select HAVE_RETHOOK
244	select HAVE_KVM
245	select HAVE_LIVEPATCH			if X86_64
246	select HAVE_MIXED_BREAKPOINTS_REGS
247	select HAVE_MOD_ARCH_SPECIFIC
248	select HAVE_MOVE_PMD
249	select HAVE_MOVE_PUD
250	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
251	select HAVE_NMI
252	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
253	select HAVE_OBJTOOL			if X86_64
254	select HAVE_OPTPROBES
255	select HAVE_PCSPKR_PLATFORM
256	select HAVE_PERF_EVENTS
257	select HAVE_PERF_EVENTS_NMI
258	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
259	select HAVE_PCI
260	select HAVE_PERF_REGS
261	select HAVE_PERF_USER_STACK_DUMP
262	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
263	select MMU_GATHER_MERGE_VMAS
264	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
265	select HAVE_REGS_AND_STACK_ACCESS_API
266	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
267	select HAVE_FUNCTION_ARG_ACCESS_API
268	select HAVE_SETUP_PER_CPU_AREA
269	select HAVE_SOFTIRQ_ON_OWN_STACK
270	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
271	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
272	select HAVE_STATIC_CALL
273	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
274	select HAVE_PREEMPT_DYNAMIC_CALL
275	select HAVE_RSEQ
276	select HAVE_RUST			if X86_64
277	select HAVE_SYSCALL_TRACEPOINTS
278	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
279	select HAVE_UNSTABLE_SCHED_CLOCK
280	select HAVE_USER_RETURN_NOTIFIER
281	select HAVE_GENERIC_VDSO
282	select HOTPLUG_PARALLEL			if SMP && X86_64
283	select HOTPLUG_SMT			if SMP
284	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
285	select IRQ_FORCED_THREADING
286	select LOCK_MM_AND_FIND_VMA
287	select NEED_PER_CPU_EMBED_FIRST_CHUNK
288	select NEED_PER_CPU_PAGE_FIRST_CHUNK
289	select NEED_SG_DMA_LENGTH
290	select PCI_DOMAINS			if PCI
291	select PCI_LOCKLESS_CONFIG		if PCI
292	select PERF_EVENTS
293	select RTC_LIB
294	select RTC_MC146818_LIB
295	select SPARSE_IRQ
296	select SYSCTL_EXCEPTION_TRACE
297	select THREAD_INFO_IN_TASK
298	select TRACE_IRQFLAGS_SUPPORT
299	select TRACE_IRQFLAGS_NMI_SUPPORT
300	select USER_STACKTRACE_SUPPORT
301	select HAVE_ARCH_KCSAN			if X86_64
302	select PROC_PID_ARCH_STATUS		if PROC_FS
303	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
304	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
305	select FUNCTION_ALIGNMENT_4B
306	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
307	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
308
309config INSTRUCTION_DECODER
310	def_bool y
311	depends on KPROBES || PERF_EVENTS || UPROBES
312
313config OUTPUT_FORMAT
314	string
315	default "elf32-i386" if X86_32
316	default "elf64-x86-64" if X86_64
317
318config LOCKDEP_SUPPORT
319	def_bool y
320
321config STACKTRACE_SUPPORT
322	def_bool y
323
324config MMU
325	def_bool y
326
327config ARCH_MMAP_RND_BITS_MIN
328	default 28 if 64BIT
329	default 8
330
331config ARCH_MMAP_RND_BITS_MAX
332	default 32 if 64BIT
333	default 16
334
335config ARCH_MMAP_RND_COMPAT_BITS_MIN
336	default 8
337
338config ARCH_MMAP_RND_COMPAT_BITS_MAX
339	default 16
340
341config SBUS
342	bool
343
344config GENERIC_ISA_DMA
345	def_bool y
346	depends on ISA_DMA_API
347
348config GENERIC_CSUM
349	bool
350	default y if KMSAN || KASAN
351
352config GENERIC_BUG
353	def_bool y
354	depends on BUG
355	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
356
357config GENERIC_BUG_RELATIVE_POINTERS
358	bool
359
360config ARCH_MAY_HAVE_PC_FDC
361	def_bool y
362	depends on ISA_DMA_API
363
364config GENERIC_CALIBRATE_DELAY
365	def_bool y
366
367config ARCH_HAS_CPU_RELAX
368	def_bool y
369
370config ARCH_HIBERNATION_POSSIBLE
371	def_bool y
372
373config ARCH_SUSPEND_POSSIBLE
374	def_bool y
375
376config AUDIT_ARCH
377	def_bool y if X86_64
378
379config KASAN_SHADOW_OFFSET
380	hex
381	depends on KASAN
382	default 0xdffffc0000000000
383
384config HAVE_INTEL_TXT
385	def_bool y
386	depends on INTEL_IOMMU && ACPI
387
388config X86_32_SMP
389	def_bool y
390	depends on X86_32 && SMP
391
392config X86_64_SMP
393	def_bool y
394	depends on X86_64 && SMP
395
396config ARCH_SUPPORTS_UPROBES
397	def_bool y
398
399config FIX_EARLYCON_MEM
400	def_bool y
401
402config DYNAMIC_PHYSICAL_MASK
403	bool
404
405config PGTABLE_LEVELS
406	int
407	default 5 if X86_5LEVEL
408	default 4 if X86_64
409	default 3 if X86_PAE
410	default 2
411
412config CC_HAS_SANE_STACKPROTECTOR
413	bool
414	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
415	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
416	help
417	  We have to make sure stack protector is unconditionally disabled if
418	  the compiler produces broken code or if it does not let us control
419	  the segment on 32-bit kernels.
420
421menu "Processor type and features"
422
423config SMP
424	bool "Symmetric multi-processing support"
425	help
426	  This enables support for systems with more than one CPU. If you have
427	  a system with only one CPU, say N. If you have a system with more
428	  than one CPU, say Y.
429
430	  If you say N here, the kernel will run on uni- and multiprocessor
431	  machines, but will use only one CPU of a multiprocessor machine. If
432	  you say Y here, the kernel will run on many, but not all,
433	  uniprocessor machines. On a uniprocessor machine, the kernel
434	  will run faster if you say N here.
435
436	  Note that if you say Y here and choose architecture "586" or
437	  "Pentium" under "Processor family", the kernel will not work on 486
438	  architectures. Similarly, multiprocessor kernels for the "PPro"
439	  architecture may not work on all Pentium based boards.
440
441	  People using multiprocessor machines who say Y here should also say
442	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
443	  Management" code will be disabled if you say Y here.
444
445	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
446	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
447	  <http://www.tldp.org/docs.html#howto>.
448
449	  If you don't know what to do here, say N.
450
451config X86_X2APIC
452	bool "Support x2apic"
453	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
454	help
455	  This enables x2apic support on CPUs that have this feature.
456
457	  This allows 32-bit apic IDs (so it can support very large systems),
458	  and accesses the local apic via MSRs not via mmio.
459
460	  Some Intel systems circa 2022 and later are locked into x2APIC mode
461	  and can not fall back to the legacy APIC modes if SGX or TDX are
462	  enabled in the BIOS. They will boot with very reduced functionality
463	  without enabling this option.
464
465	  If you don't know what to do here, say N.
466
467config X86_MPPARSE
468	bool "Enable MPS table" if ACPI
469	default y
470	depends on X86_LOCAL_APIC
471	help
472	  For old smp systems that do not have proper acpi support. Newer systems
473	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
474
475config GOLDFISH
476	def_bool y
477	depends on X86_GOLDFISH
478
479config X86_CPU_RESCTRL
480	bool "x86 CPU resource control support"
481	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
482	select KERNFS
483	select PROC_CPU_RESCTRL		if PROC_FS
484	help
485	  Enable x86 CPU resource control support.
486
487	  Provide support for the allocation and monitoring of system resources
488	  usage by the CPU.
489
490	  Intel calls this Intel Resource Director Technology
491	  (Intel(R) RDT). More information about RDT can be found in the
492	  Intel x86 Architecture Software Developer Manual.
493
494	  AMD calls this AMD Platform Quality of Service (AMD QoS).
495	  More information about AMD QoS can be found in the AMD64 Technology
496	  Platform Quality of Service Extensions manual.
497
498	  Say N if unsure.
499
500if X86_32
501config X86_BIGSMP
502	bool "Support for big SMP systems with more than 8 CPUs"
503	depends on SMP
504	help
505	  This option is needed for the systems that have more than 8 CPUs.
506
507config X86_EXTENDED_PLATFORM
508	bool "Support for extended (non-PC) x86 platforms"
509	default y
510	help
511	  If you disable this option then the kernel will only support
512	  standard PC platforms. (which covers the vast majority of
513	  systems out there.)
514
515	  If you enable this option then you'll be able to select support
516	  for the following (non-PC) 32 bit x86 platforms:
517		Goldfish (Android emulator)
518		AMD Elan
519		RDC R-321x SoC
520		SGI 320/540 (Visual Workstation)
521		STA2X11-based (e.g. Northville)
522		Moorestown MID devices
523
524	  If you have one of these systems, or if you want to build a
525	  generic distribution kernel, say Y here - otherwise say N.
526endif # X86_32
527
528if X86_64
529config X86_EXTENDED_PLATFORM
530	bool "Support for extended (non-PC) x86 platforms"
531	default y
532	help
533	  If you disable this option then the kernel will only support
534	  standard PC platforms. (which covers the vast majority of
535	  systems out there.)
536
537	  If you enable this option then you'll be able to select support
538	  for the following (non-PC) 64 bit x86 platforms:
539		Numascale NumaChip
540		ScaleMP vSMP
541		SGI Ultraviolet
542
543	  If you have one of these systems, or if you want to build a
544	  generic distribution kernel, say Y here - otherwise say N.
545endif # X86_64
546# This is an alphabetically sorted list of 64 bit extended platforms
547# Please maintain the alphabetic order if and when there are additions
548config X86_NUMACHIP
549	bool "Numascale NumaChip"
550	depends on X86_64
551	depends on X86_EXTENDED_PLATFORM
552	depends on NUMA
553	depends on SMP
554	depends on X86_X2APIC
555	depends on PCI_MMCONFIG
556	help
557	  Adds support for Numascale NumaChip large-SMP systems. Needed to
558	  enable more than ~168 cores.
559	  If you don't have one of these, you should say N here.
560
561config X86_VSMP
562	bool "ScaleMP vSMP"
563	select HYPERVISOR_GUEST
564	select PARAVIRT
565	depends on X86_64 && PCI
566	depends on X86_EXTENDED_PLATFORM
567	depends on SMP
568	help
569	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
570	  supposed to run on these EM64T-based machines.  Only choose this option
571	  if you have one of these machines.
572
573config X86_UV
574	bool "SGI Ultraviolet"
575	depends on X86_64
576	depends on X86_EXTENDED_PLATFORM
577	depends on NUMA
578	depends on EFI
579	depends on KEXEC_CORE
580	depends on X86_X2APIC
581	depends on PCI
582	help
583	  This option is needed in order to support SGI Ultraviolet systems.
584	  If you don't have one of these, you should say N here.
585
586# Following is an alphabetically sorted list of 32 bit extended platforms
587# Please maintain the alphabetic order if and when there are additions
588
589config X86_GOLDFISH
590	bool "Goldfish (Virtual Platform)"
591	depends on X86_EXTENDED_PLATFORM
592	help
593	  Enable support for the Goldfish virtual platform used primarily
594	  for Android development. Unless you are building for the Android
595	  Goldfish emulator say N here.
596
597config X86_INTEL_CE
598	bool "CE4100 TV platform"
599	depends on PCI
600	depends on PCI_GODIRECT
601	depends on X86_IO_APIC
602	depends on X86_32
603	depends on X86_EXTENDED_PLATFORM
604	select X86_REBOOTFIXUPS
605	select OF
606	select OF_EARLY_FLATTREE
607	help
608	  Select for the Intel CE media processor (CE4100) SOC.
609	  This option compiles in support for the CE4100 SOC for settop
610	  boxes and media devices.
611
612config X86_INTEL_MID
613	bool "Intel MID platform support"
614	depends on X86_EXTENDED_PLATFORM
615	depends on X86_PLATFORM_DEVICES
616	depends on PCI
617	depends on X86_64 || (PCI_GOANY && X86_32)
618	depends on X86_IO_APIC
619	select I2C
620	select DW_APB_TIMER
621	select INTEL_SCU_PCI
622	help
623	  Select to build a kernel capable of supporting Intel MID (Mobile
624	  Internet Device) platform systems which do not have the PCI legacy
625	  interfaces. If you are building for a PC class system say N here.
626
627	  Intel MID platforms are based on an Intel processor and chipset which
628	  consume less power than most of the x86 derivatives.
629
630config X86_INTEL_QUARK
631	bool "Intel Quark platform support"
632	depends on X86_32
633	depends on X86_EXTENDED_PLATFORM
634	depends on X86_PLATFORM_DEVICES
635	depends on X86_TSC
636	depends on PCI
637	depends on PCI_GOANY
638	depends on X86_IO_APIC
639	select IOSF_MBI
640	select INTEL_IMR
641	select COMMON_CLK
642	help
643	  Select to include support for Quark X1000 SoC.
644	  Say Y here if you have a Quark based system such as the Arduino
645	  compatible Intel Galileo.
646
647config X86_INTEL_LPSS
648	bool "Intel Low Power Subsystem Support"
649	depends on X86 && ACPI && PCI
650	select COMMON_CLK
651	select PINCTRL
652	select IOSF_MBI
653	help
654	  Select to build support for Intel Low Power Subsystem such as
655	  found on Intel Lynxpoint PCH. Selecting this option enables
656	  things like clock tree (common clock framework) and pincontrol
657	  which are needed by the LPSS peripheral drivers.
658
659config X86_AMD_PLATFORM_DEVICE
660	bool "AMD ACPI2Platform devices support"
661	depends on ACPI
662	select COMMON_CLK
663	select PINCTRL
664	help
665	  Select to interpret AMD specific ACPI device to platform device
666	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
667	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
668	  implemented under PINCTRL subsystem.
669
670config IOSF_MBI
671	tristate "Intel SoC IOSF Sideband support for SoC platforms"
672	depends on PCI
673	help
674	  This option enables sideband register access support for Intel SoC
675	  platforms. On these platforms the IOSF sideband is used in lieu of
676	  MSR's for some register accesses, mostly but not limited to thermal
677	  and power. Drivers may query the availability of this device to
678	  determine if they need the sideband in order to work on these
679	  platforms. The sideband is available on the following SoC products.
680	  This list is not meant to be exclusive.
681	   - BayTrail
682	   - Braswell
683	   - Quark
684
685	  You should say Y if you are running a kernel on one of these SoC's.
686
687config IOSF_MBI_DEBUG
688	bool "Enable IOSF sideband access through debugfs"
689	depends on IOSF_MBI && DEBUG_FS
690	help
691	  Select this option to expose the IOSF sideband access registers (MCR,
692	  MDR, MCRX) through debugfs to write and read register information from
693	  different units on the SoC. This is most useful for obtaining device
694	  state information for debug and analysis. As this is a general access
695	  mechanism, users of this option would have specific knowledge of the
696	  device they want to access.
697
698	  If you don't require the option or are in doubt, say N.
699
700config X86_RDC321X
701	bool "RDC R-321x SoC"
702	depends on X86_32
703	depends on X86_EXTENDED_PLATFORM
704	select M486
705	select X86_REBOOTFIXUPS
706	help
707	  This option is needed for RDC R-321x system-on-chip, also known
708	  as R-8610-(G).
709	  If you don't have one of these chips, you should say N here.
710
711config X86_32_NON_STANDARD
712	bool "Support non-standard 32-bit SMP architectures"
713	depends on X86_32 && SMP
714	depends on X86_EXTENDED_PLATFORM
715	help
716	  This option compiles in the bigsmp and STA2X11 default
717	  subarchitectures.  It is intended for a generic binary
718	  kernel. If you select them all, kernel will probe it one by
719	  one and will fallback to default.
720
721# Alphabetically sorted list of Non standard 32 bit platforms
722
723config X86_SUPPORTS_MEMORY_FAILURE
724	def_bool y
725	# MCE code calls memory_failure():
726	depends on X86_MCE
727	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
728	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
729	depends on X86_64 || !SPARSEMEM
730	select ARCH_SUPPORTS_MEMORY_FAILURE
731
732config STA2X11
733	bool "STA2X11 Companion Chip Support"
734	depends on X86_32_NON_STANDARD && PCI
735	select SWIOTLB
736	select MFD_STA2X11
737	select GPIOLIB
738	help
739	  This adds support for boards based on the STA2X11 IO-Hub,
740	  a.k.a. "ConneXt". The chip is used in place of the standard
741	  PC chipset, so all "standard" peripherals are missing. If this
742	  option is selected the kernel will still be able to boot on
743	  standard PC machines.
744
745config X86_32_IRIS
746	tristate "Eurobraille/Iris poweroff module"
747	depends on X86_32
748	help
749	  The Iris machines from EuroBraille do not have APM or ACPI support
750	  to shut themselves down properly.  A special I/O sequence is
751	  needed to do so, which is what this module does at
752	  kernel shutdown.
753
754	  This is only for Iris machines from EuroBraille.
755
756	  If unused, say N.
757
758config SCHED_OMIT_FRAME_POINTER
759	def_bool y
760	prompt "Single-depth WCHAN output"
761	depends on X86
762	help
763	  Calculate simpler /proc/<PID>/wchan values. If this option
764	  is disabled then wchan values will recurse back to the
765	  caller function. This provides more accurate wchan values,
766	  at the expense of slightly more scheduling overhead.
767
768	  If in doubt, say "Y".
769
770menuconfig HYPERVISOR_GUEST
771	bool "Linux guest support"
772	help
773	  Say Y here to enable options for running Linux under various hyper-
774	  visors. This option enables basic hypervisor detection and platform
775	  setup.
776
777	  If you say N, all options in this submenu will be skipped and
778	  disabled, and Linux guest support won't be built in.
779
780if HYPERVISOR_GUEST
781
782config PARAVIRT
783	bool "Enable paravirtualization code"
784	depends on HAVE_STATIC_CALL
785	help
786	  This changes the kernel so it can modify itself when it is run
787	  under a hypervisor, potentially improving performance significantly
788	  over full virtualization.  However, when run without a hypervisor
789	  the kernel is theoretically slower and slightly larger.
790
791config PARAVIRT_XXL
792	bool
793
794config PARAVIRT_DEBUG
795	bool "paravirt-ops debugging"
796	depends on PARAVIRT && DEBUG_KERNEL
797	help
798	  Enable to debug paravirt_ops internals.  Specifically, BUG if
799	  a paravirt_op is missing when it is called.
800
801config PARAVIRT_SPINLOCKS
802	bool "Paravirtualization layer for spinlocks"
803	depends on PARAVIRT && SMP
804	help
805	  Paravirtualized spinlocks allow a pvops backend to replace the
806	  spinlock implementation with something virtualization-friendly
807	  (for example, block the virtual CPU rather than spinning).
808
809	  It has a minimal impact on native kernels and gives a nice performance
810	  benefit on paravirtualized KVM / Xen kernels.
811
812	  If you are unsure how to answer this question, answer Y.
813
814config X86_HV_CALLBACK_VECTOR
815	def_bool n
816
817source "arch/x86/xen/Kconfig"
818
819config KVM_GUEST
820	bool "KVM Guest support (including kvmclock)"
821	depends on PARAVIRT
822	select PARAVIRT_CLOCK
823	select ARCH_CPUIDLE_HALTPOLL
824	select X86_HV_CALLBACK_VECTOR
825	default y
826	help
827	  This option enables various optimizations for running under the KVM
828	  hypervisor. It includes a paravirtualized clock, so that instead
829	  of relying on a PIT (or probably other) emulation by the
830	  underlying device model, the host provides the guest with
831	  timing infrastructure such as time of day, and system time
832
833config ARCH_CPUIDLE_HALTPOLL
834	def_bool n
835	prompt "Disable host haltpoll when loading haltpoll driver"
836	help
837	  If virtualized under KVM, disable host haltpoll.
838
839config PVH
840	bool "Support for running PVH guests"
841	help
842	  This option enables the PVH entry point for guest virtual machines
843	  as specified in the x86/HVM direct boot ABI.
844
845config PARAVIRT_TIME_ACCOUNTING
846	bool "Paravirtual steal time accounting"
847	depends on PARAVIRT
848	help
849	  Select this option to enable fine granularity task steal time
850	  accounting. Time spent executing other tasks in parallel with
851	  the current vCPU is discounted from the vCPU power. To account for
852	  that, there can be a small performance impact.
853
854	  If in doubt, say N here.
855
856config PARAVIRT_CLOCK
857	bool
858
859config JAILHOUSE_GUEST
860	bool "Jailhouse non-root cell support"
861	depends on X86_64 && PCI
862	select X86_PM_TIMER
863	help
864	  This option allows to run Linux as guest in a Jailhouse non-root
865	  cell. You can leave this option disabled if you only want to start
866	  Jailhouse and run Linux afterwards in the root cell.
867
868config ACRN_GUEST
869	bool "ACRN Guest support"
870	depends on X86_64
871	select X86_HV_CALLBACK_VECTOR
872	help
873	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
874	  a flexible, lightweight reference open-source hypervisor, built with
875	  real-time and safety-criticality in mind. It is built for embedded
876	  IOT with small footprint and real-time features. More details can be
877	  found in https://projectacrn.org/.
878
879config INTEL_TDX_GUEST
880	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
881	depends on X86_64 && CPU_SUP_INTEL
882	depends on X86_X2APIC
883	depends on EFI_STUB
884	select ARCH_HAS_CC_PLATFORM
885	select X86_MEM_ENCRYPT
886	select X86_MCE
887	select UNACCEPTED_MEMORY
888	help
889	  Support running as a guest under Intel TDX.  Without this support,
890	  the guest kernel can not boot or run under TDX.
891	  TDX includes memory encryption and integrity capabilities
892	  which protect the confidentiality and integrity of guest
893	  memory contents and CPU state. TDX guests are protected from
894	  some attacks from the VMM.
895
896endif # HYPERVISOR_GUEST
897
898source "arch/x86/Kconfig.cpu"
899
900config HPET_TIMER
901	def_bool X86_64
902	prompt "HPET Timer Support" if X86_32
903	help
904	  Use the IA-PC HPET (High Precision Event Timer) to manage
905	  time in preference to the PIT and RTC, if a HPET is
906	  present.
907	  HPET is the next generation timer replacing legacy 8254s.
908	  The HPET provides a stable time base on SMP
909	  systems, unlike the TSC, but it is more expensive to access,
910	  as it is off-chip.  The interface used is documented
911	  in the HPET spec, revision 1.
912
913	  You can safely choose Y here.  However, HPET will only be
914	  activated if the platform and the BIOS support this feature.
915	  Otherwise the 8254 will be used for timing services.
916
917	  Choose N to continue using the legacy 8254 timer.
918
919config HPET_EMULATE_RTC
920	def_bool y
921	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
922
923# Mark as expert because too many people got it wrong.
924# The code disables itself when not needed.
925config DMI
926	default y
927	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
928	bool "Enable DMI scanning" if EXPERT
929	help
930	  Enabled scanning of DMI to identify machine quirks. Say Y
931	  here unless you have verified that your setup is not
932	  affected by entries in the DMI blacklist. Required by PNP
933	  BIOS code.
934
935config GART_IOMMU
936	bool "Old AMD GART IOMMU support"
937	select DMA_OPS
938	select IOMMU_HELPER
939	select SWIOTLB
940	depends on X86_64 && PCI && AMD_NB
941	help
942	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
943	  GART based hardware IOMMUs.
944
945	  The GART supports full DMA access for devices with 32-bit access
946	  limitations, on systems with more than 3 GB. This is usually needed
947	  for USB, sound, many IDE/SATA chipsets and some other devices.
948
949	  Newer systems typically have a modern AMD IOMMU, supported via
950	  the CONFIG_AMD_IOMMU=y config option.
951
952	  In normal configurations this driver is only active when needed:
953	  there's more than 3 GB of memory and the system contains a
954	  32-bit limited device.
955
956	  If unsure, say Y.
957
958config BOOT_VESA_SUPPORT
959	bool
960	help
961	  If true, at least one selected framebuffer driver can take advantage
962	  of VESA video modes set at an early boot stage via the vga= parameter.
963
964config MAXSMP
965	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
966	depends on X86_64 && SMP && DEBUG_KERNEL
967	select CPUMASK_OFFSTACK
968	help
969	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
970	  If unsure, say N.
971
972#
973# The maximum number of CPUs supported:
974#
975# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
976# and which can be configured interactively in the
977# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
978#
979# The ranges are different on 32-bit and 64-bit kernels, depending on
980# hardware capabilities and scalability features of the kernel.
981#
982# ( If MAXSMP is enabled we just use the highest possible value and disable
983#   interactive configuration. )
984#
985
986config NR_CPUS_RANGE_BEGIN
987	int
988	default NR_CPUS_RANGE_END if MAXSMP
989	default    1 if !SMP
990	default    2
991
992config NR_CPUS_RANGE_END
993	int
994	depends on X86_32
995	default   64 if  SMP &&  X86_BIGSMP
996	default    8 if  SMP && !X86_BIGSMP
997	default    1 if !SMP
998
999config NR_CPUS_RANGE_END
1000	int
1001	depends on X86_64
1002	default 8192 if  SMP && CPUMASK_OFFSTACK
1003	default  512 if  SMP && !CPUMASK_OFFSTACK
1004	default    1 if !SMP
1005
1006config NR_CPUS_DEFAULT
1007	int
1008	depends on X86_32
1009	default   32 if  X86_BIGSMP
1010	default    8 if  SMP
1011	default    1 if !SMP
1012
1013config NR_CPUS_DEFAULT
1014	int
1015	depends on X86_64
1016	default 8192 if  MAXSMP
1017	default   64 if  SMP
1018	default    1 if !SMP
1019
1020config NR_CPUS
1021	int "Maximum number of CPUs" if SMP && !MAXSMP
1022	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1023	default NR_CPUS_DEFAULT
1024	help
1025	  This allows you to specify the maximum number of CPUs which this
1026	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1027	  supported value is 8192, otherwise the maximum value is 512.  The
1028	  minimum value which makes sense is 2.
1029
1030	  This is purely to save memory: each supported CPU adds about 8KB
1031	  to the kernel image.
1032
1033config SCHED_CLUSTER
1034	bool "Cluster scheduler support"
1035	depends on SMP
1036	default y
1037	help
1038	  Cluster scheduler support improves the CPU scheduler's decision
1039	  making when dealing with machines that have clusters of CPUs.
1040	  Cluster usually means a couple of CPUs which are placed closely
1041	  by sharing mid-level caches, last-level cache tags or internal
1042	  busses.
1043
1044config SCHED_SMT
1045	def_bool y if SMP
1046
1047config SCHED_MC
1048	def_bool y
1049	prompt "Multi-core scheduler support"
1050	depends on SMP
1051	help
1052	  Multi-core scheduler support improves the CPU scheduler's decision
1053	  making when dealing with multi-core CPU chips at a cost of slightly
1054	  increased overhead in some places. If unsure say N here.
1055
1056config SCHED_MC_PRIO
1057	bool "CPU core priorities scheduler support"
1058	depends on SCHED_MC && CPU_SUP_INTEL
1059	select X86_INTEL_PSTATE
1060	select CPU_FREQ
1061	default y
1062	help
1063	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1064	  core ordering determined at manufacturing time, which allows
1065	  certain cores to reach higher turbo frequencies (when running
1066	  single threaded workloads) than others.
1067
1068	  Enabling this kernel feature teaches the scheduler about
1069	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1070	  scheduler's CPU selection logic accordingly, so that higher
1071	  overall system performance can be achieved.
1072
1073	  This feature will have no effect on CPUs without this feature.
1074
1075	  If unsure say Y here.
1076
1077config UP_LATE_INIT
1078	def_bool y
1079	depends on !SMP && X86_LOCAL_APIC
1080
1081config X86_UP_APIC
1082	bool "Local APIC support on uniprocessors" if !PCI_MSI
1083	default PCI_MSI
1084	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1085	help
1086	  A local APIC (Advanced Programmable Interrupt Controller) is an
1087	  integrated interrupt controller in the CPU. If you have a single-CPU
1088	  system which has a processor with a local APIC, you can say Y here to
1089	  enable and use it. If you say Y here even though your machine doesn't
1090	  have a local APIC, then the kernel will still run with no slowdown at
1091	  all. The local APIC supports CPU-generated self-interrupts (timer,
1092	  performance counters), and the NMI watchdog which detects hard
1093	  lockups.
1094
1095config X86_UP_IOAPIC
1096	bool "IO-APIC support on uniprocessors"
1097	depends on X86_UP_APIC
1098	help
1099	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1100	  SMP-capable replacement for PC-style interrupt controllers. Most
1101	  SMP systems and many recent uniprocessor systems have one.
1102
1103	  If you have a single-CPU system with an IO-APIC, you can say Y here
1104	  to use it. If you say Y here even though your machine doesn't have
1105	  an IO-APIC, then the kernel will still run with no slowdown at all.
1106
1107config X86_LOCAL_APIC
1108	def_bool y
1109	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1110	select IRQ_DOMAIN_HIERARCHY
1111
1112config X86_IO_APIC
1113	def_bool y
1114	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1115
1116config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1117	bool "Reroute for broken boot IRQs"
1118	depends on X86_IO_APIC
1119	help
1120	  This option enables a workaround that fixes a source of
1121	  spurious interrupts. This is recommended when threaded
1122	  interrupt handling is used on systems where the generation of
1123	  superfluous "boot interrupts" cannot be disabled.
1124
1125	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1126	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1127	  kernel does during interrupt handling). On chipsets where this
1128	  boot IRQ generation cannot be disabled, this workaround keeps
1129	  the original IRQ line masked so that only the equivalent "boot
1130	  IRQ" is delivered to the CPUs. The workaround also tells the
1131	  kernel to set up the IRQ handler on the boot IRQ line. In this
1132	  way only one interrupt is delivered to the kernel. Otherwise
1133	  the spurious second interrupt may cause the kernel to bring
1134	  down (vital) interrupt lines.
1135
1136	  Only affects "broken" chipsets. Interrupt sharing may be
1137	  increased on these systems.
1138
1139config X86_MCE
1140	bool "Machine Check / overheating reporting"
1141	select GENERIC_ALLOCATOR
1142	default y
1143	help
1144	  Machine Check support allows the processor to notify the
1145	  kernel if it detects a problem (e.g. overheating, data corruption).
1146	  The action the kernel takes depends on the severity of the problem,
1147	  ranging from warning messages to halting the machine.
1148
1149config X86_MCELOG_LEGACY
1150	bool "Support for deprecated /dev/mcelog character device"
1151	depends on X86_MCE
1152	help
1153	  Enable support for /dev/mcelog which is needed by the old mcelog
1154	  userspace logging daemon. Consider switching to the new generation
1155	  rasdaemon solution.
1156
1157config X86_MCE_INTEL
1158	def_bool y
1159	prompt "Intel MCE features"
1160	depends on X86_MCE && X86_LOCAL_APIC
1161	help
1162	  Additional support for intel specific MCE features such as
1163	  the thermal monitor.
1164
1165config X86_MCE_AMD
1166	def_bool y
1167	prompt "AMD MCE features"
1168	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1169	help
1170	  Additional support for AMD specific MCE features such as
1171	  the DRAM Error Threshold.
1172
1173config X86_ANCIENT_MCE
1174	bool "Support for old Pentium 5 / WinChip machine checks"
1175	depends on X86_32 && X86_MCE
1176	help
1177	  Include support for machine check handling on old Pentium 5 or WinChip
1178	  systems. These typically need to be enabled explicitly on the command
1179	  line.
1180
1181config X86_MCE_THRESHOLD
1182	depends on X86_MCE_AMD || X86_MCE_INTEL
1183	def_bool y
1184
1185config X86_MCE_INJECT
1186	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1187	tristate "Machine check injector support"
1188	help
1189	  Provide support for injecting machine checks for testing purposes.
1190	  If you don't know what a machine check is and you don't do kernel
1191	  QA it is safe to say n.
1192
1193source "arch/x86/events/Kconfig"
1194
1195config X86_LEGACY_VM86
1196	bool "Legacy VM86 support"
1197	depends on X86_32
1198	help
1199	  This option allows user programs to put the CPU into V8086
1200	  mode, which is an 80286-era approximation of 16-bit real mode.
1201
1202	  Some very old versions of X and/or vbetool require this option
1203	  for user mode setting.  Similarly, DOSEMU will use it if
1204	  available to accelerate real mode DOS programs.  However, any
1205	  recent version of DOSEMU, X, or vbetool should be fully
1206	  functional even without kernel VM86 support, as they will all
1207	  fall back to software emulation. Nevertheless, if you are using
1208	  a 16-bit DOS program where 16-bit performance matters, vm86
1209	  mode might be faster than emulation and you might want to
1210	  enable this option.
1211
1212	  Note that any app that works on a 64-bit kernel is unlikely to
1213	  need this option, as 64-bit kernels don't, and can't, support
1214	  V8086 mode. This option is also unrelated to 16-bit protected
1215	  mode and is not needed to run most 16-bit programs under Wine.
1216
1217	  Enabling this option increases the complexity of the kernel
1218	  and slows down exception handling a tiny bit.
1219
1220	  If unsure, say N here.
1221
1222config VM86
1223	bool
1224	default X86_LEGACY_VM86
1225
1226config X86_16BIT
1227	bool "Enable support for 16-bit segments" if EXPERT
1228	default y
1229	depends on MODIFY_LDT_SYSCALL
1230	help
1231	  This option is required by programs like Wine to run 16-bit
1232	  protected mode legacy code on x86 processors.  Disabling
1233	  this option saves about 300 bytes on i386, or around 6K text
1234	  plus 16K runtime memory on x86-64,
1235
1236config X86_ESPFIX32
1237	def_bool y
1238	depends on X86_16BIT && X86_32
1239
1240config X86_ESPFIX64
1241	def_bool y
1242	depends on X86_16BIT && X86_64
1243
1244config X86_VSYSCALL_EMULATION
1245	bool "Enable vsyscall emulation" if EXPERT
1246	default y
1247	depends on X86_64
1248	help
1249	  This enables emulation of the legacy vsyscall page.  Disabling
1250	  it is roughly equivalent to booting with vsyscall=none, except
1251	  that it will also disable the helpful warning if a program
1252	  tries to use a vsyscall.  With this option set to N, offending
1253	  programs will just segfault, citing addresses of the form
1254	  0xffffffffff600?00.
1255
1256	  This option is required by many programs built before 2013, and
1257	  care should be used even with newer programs if set to N.
1258
1259	  Disabling this option saves about 7K of kernel size and
1260	  possibly 4K of additional runtime pagetable memory.
1261
1262config X86_IOPL_IOPERM
1263	bool "IOPERM and IOPL Emulation"
1264	default y
1265	help
1266	  This enables the ioperm() and iopl() syscalls which are necessary
1267	  for legacy applications.
1268
1269	  Legacy IOPL support is an overbroad mechanism which allows user
1270	  space aside of accessing all 65536 I/O ports also to disable
1271	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1272	  capabilities and permission from potentially active security
1273	  modules.
1274
1275	  The emulation restricts the functionality of the syscall to
1276	  only allowing the full range I/O port access, but prevents the
1277	  ability to disable interrupts from user space which would be
1278	  granted if the hardware IOPL mechanism would be used.
1279
1280config TOSHIBA
1281	tristate "Toshiba Laptop support"
1282	depends on X86_32
1283	help
1284	  This adds a driver to safely access the System Management Mode of
1285	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1286	  not work on models with a Phoenix BIOS. The System Management Mode
1287	  is used to set the BIOS and power saving options on Toshiba portables.
1288
1289	  For information on utilities to make use of this driver see the
1290	  Toshiba Linux utilities web site at:
1291	  <http://www.buzzard.org.uk/toshiba/>.
1292
1293	  Say Y if you intend to run this kernel on a Toshiba portable.
1294	  Say N otherwise.
1295
1296config X86_REBOOTFIXUPS
1297	bool "Enable X86 board specific fixups for reboot"
1298	depends on X86_32
1299	help
1300	  This enables chipset and/or board specific fixups to be done
1301	  in order to get reboot to work correctly. This is only needed on
1302	  some combinations of hardware and BIOS. The symptom, for which
1303	  this config is intended, is when reboot ends with a stalled/hung
1304	  system.
1305
1306	  Currently, the only fixup is for the Geode machines using
1307	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1308
1309	  Say Y if you want to enable the fixup. Currently, it's safe to
1310	  enable this option even if you don't need it.
1311	  Say N otherwise.
1312
1313config MICROCODE
1314	def_bool y
1315	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1316	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1317
1318config MICROCODE_LATE_LOADING
1319	bool "Late microcode loading (DANGEROUS)"
1320	default n
1321	depends on MICROCODE && SMP
1322	help
1323	  Loading microcode late, when the system is up and executing instructions
1324	  is a tricky business and should be avoided if possible. Just the sequence
1325	  of synchronizing all cores and SMT threads is one fragile dance which does
1326	  not guarantee that cores might not softlock after the loading. Therefore,
1327	  use this at your own risk. Late loading taints the kernel unless the
1328	  microcode header indicates that it is safe for late loading via the
1329	  minimal revision check. This minimal revision check can be enforced on
1330	  the kernel command line with "microcode.minrev=Y".
1331
1332config MICROCODE_LATE_FORCE_MINREV
1333	bool "Enforce late microcode loading minimal revision check"
1334	default n
1335	depends on MICROCODE_LATE_LOADING
1336	help
1337	  To prevent that users load microcode late which modifies already
1338	  in use features, newer microcode patches have a minimum revision field
1339	  in the microcode header, which tells the kernel which minimum
1340	  revision must be active in the CPU to safely load that new microcode
1341	  late into the running system. If disabled the check will not
1342	  be enforced but the kernel will be tainted when the minimal
1343	  revision check fails.
1344
1345	  This minimal revision check can also be controlled via the
1346	  "microcode.minrev" parameter on the kernel command line.
1347
1348	  If unsure say Y.
1349
1350config X86_MSR
1351	tristate "/dev/cpu/*/msr - Model-specific register support"
1352	help
1353	  This device gives privileged processes access to the x86
1354	  Model-Specific Registers (MSRs).  It is a character device with
1355	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1356	  MSR accesses are directed to a specific CPU on multi-processor
1357	  systems.
1358
1359config X86_CPUID
1360	tristate "/dev/cpu/*/cpuid - CPU information support"
1361	help
1362	  This device gives processes access to the x86 CPUID instruction to
1363	  be executed on a specific processor.  It is a character device
1364	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1365	  /dev/cpu/31/cpuid.
1366
1367choice
1368	prompt "High Memory Support"
1369	default HIGHMEM4G
1370	depends on X86_32
1371
1372config NOHIGHMEM
1373	bool "off"
1374	help
1375	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1376	  However, the address space of 32-bit x86 processors is only 4
1377	  Gigabytes large. That means that, if you have a large amount of
1378	  physical memory, not all of it can be "permanently mapped" by the
1379	  kernel. The physical memory that's not permanently mapped is called
1380	  "high memory".
1381
1382	  If you are compiling a kernel which will never run on a machine with
1383	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1384	  choice and suitable for most users). This will result in a "3GB/1GB"
1385	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1386	  space and the remaining part of the 4GB virtual memory space is used
1387	  by the kernel to permanently map as much physical memory as
1388	  possible.
1389
1390	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1391	  answer "4GB" here.
1392
1393	  If more than 4 Gigabytes is used then answer "64GB" here. This
1394	  selection turns Intel PAE (Physical Address Extension) mode on.
1395	  PAE implements 3-level paging on IA32 processors. PAE is fully
1396	  supported by Linux, PAE mode is implemented on all recent Intel
1397	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1398	  then the kernel will not boot on CPUs that don't support PAE!
1399
1400	  The actual amount of total physical memory will either be
1401	  auto detected or can be forced by using a kernel command line option
1402	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1403	  your boot loader (lilo or loadlin) about how to pass options to the
1404	  kernel at boot time.)
1405
1406	  If unsure, say "off".
1407
1408config HIGHMEM4G
1409	bool "4GB"
1410	help
1411	  Select this if you have a 32-bit processor and between 1 and 4
1412	  gigabytes of physical RAM.
1413
1414config HIGHMEM64G
1415	bool "64GB"
1416	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1417	select X86_PAE
1418	help
1419	  Select this if you have a 32-bit processor and more than 4
1420	  gigabytes of physical RAM.
1421
1422endchoice
1423
1424choice
1425	prompt "Memory split" if EXPERT
1426	default VMSPLIT_3G
1427	depends on X86_32
1428	help
1429	  Select the desired split between kernel and user memory.
1430
1431	  If the address range available to the kernel is less than the
1432	  physical memory installed, the remaining memory will be available
1433	  as "high memory". Accessing high memory is a little more costly
1434	  than low memory, as it needs to be mapped into the kernel first.
1435	  Note that increasing the kernel address space limits the range
1436	  available to user programs, making the address space there
1437	  tighter.  Selecting anything other than the default 3G/1G split
1438	  will also likely make your kernel incompatible with binary-only
1439	  kernel modules.
1440
1441	  If you are not absolutely sure what you are doing, leave this
1442	  option alone!
1443
1444	config VMSPLIT_3G
1445		bool "3G/1G user/kernel split"
1446	config VMSPLIT_3G_OPT
1447		depends on !X86_PAE
1448		bool "3G/1G user/kernel split (for full 1G low memory)"
1449	config VMSPLIT_2G
1450		bool "2G/2G user/kernel split"
1451	config VMSPLIT_2G_OPT
1452		depends on !X86_PAE
1453		bool "2G/2G user/kernel split (for full 2G low memory)"
1454	config VMSPLIT_1G
1455		bool "1G/3G user/kernel split"
1456endchoice
1457
1458config PAGE_OFFSET
1459	hex
1460	default 0xB0000000 if VMSPLIT_3G_OPT
1461	default 0x80000000 if VMSPLIT_2G
1462	default 0x78000000 if VMSPLIT_2G_OPT
1463	default 0x40000000 if VMSPLIT_1G
1464	default 0xC0000000
1465	depends on X86_32
1466
1467config HIGHMEM
1468	def_bool y
1469	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1470
1471config X86_PAE
1472	bool "PAE (Physical Address Extension) Support"
1473	depends on X86_32 && !HIGHMEM4G
1474	select PHYS_ADDR_T_64BIT
1475	select SWIOTLB
1476	help
1477	  PAE is required for NX support, and furthermore enables
1478	  larger swapspace support for non-overcommit purposes. It
1479	  has the cost of more pagetable lookup overhead, and also
1480	  consumes more pagetable space per process.
1481
1482config X86_5LEVEL
1483	bool "Enable 5-level page tables support"
1484	default y
1485	select DYNAMIC_MEMORY_LAYOUT
1486	select SPARSEMEM_VMEMMAP
1487	depends on X86_64
1488	help
1489	  5-level paging enables access to larger address space:
1490	  up to 128 PiB of virtual address space and 4 PiB of
1491	  physical address space.
1492
1493	  It will be supported by future Intel CPUs.
1494
1495	  A kernel with the option enabled can be booted on machines that
1496	  support 4- or 5-level paging.
1497
1498	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1499	  information.
1500
1501	  Say N if unsure.
1502
1503config X86_DIRECT_GBPAGES
1504	def_bool y
1505	depends on X86_64
1506	help
1507	  Certain kernel features effectively disable kernel
1508	  linear 1 GB mappings (even if the CPU otherwise
1509	  supports them), so don't confuse the user by printing
1510	  that we have them enabled.
1511
1512config X86_CPA_STATISTICS
1513	bool "Enable statistic for Change Page Attribute"
1514	depends on DEBUG_FS
1515	help
1516	  Expose statistics about the Change Page Attribute mechanism, which
1517	  helps to determine the effectiveness of preserving large and huge
1518	  page mappings when mapping protections are changed.
1519
1520config X86_MEM_ENCRYPT
1521	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1522	select DYNAMIC_PHYSICAL_MASK
1523	def_bool n
1524
1525config AMD_MEM_ENCRYPT
1526	bool "AMD Secure Memory Encryption (SME) support"
1527	depends on X86_64 && CPU_SUP_AMD
1528	depends on EFI_STUB
1529	select DMA_COHERENT_POOL
1530	select ARCH_USE_MEMREMAP_PROT
1531	select INSTRUCTION_DECODER
1532	select ARCH_HAS_CC_PLATFORM
1533	select X86_MEM_ENCRYPT
1534	select UNACCEPTED_MEMORY
1535	help
1536	  Say yes to enable support for the encryption of system memory.
1537	  This requires an AMD processor that supports Secure Memory
1538	  Encryption (SME).
1539
1540# Common NUMA Features
1541config NUMA
1542	bool "NUMA Memory Allocation and Scheduler Support"
1543	depends on SMP
1544	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1545	default y if X86_BIGSMP
1546	select USE_PERCPU_NUMA_NODE_ID
1547	help
1548	  Enable NUMA (Non-Uniform Memory Access) support.
1549
1550	  The kernel will try to allocate memory used by a CPU on the
1551	  local memory controller of the CPU and add some more
1552	  NUMA awareness to the kernel.
1553
1554	  For 64-bit this is recommended if the system is Intel Core i7
1555	  (or later), AMD Opteron, or EM64T NUMA.
1556
1557	  For 32-bit this is only needed if you boot a 32-bit
1558	  kernel on a 64-bit NUMA platform.
1559
1560	  Otherwise, you should say N.
1561
1562config AMD_NUMA
1563	def_bool y
1564	prompt "Old style AMD Opteron NUMA detection"
1565	depends on X86_64 && NUMA && PCI
1566	help
1567	  Enable AMD NUMA node topology detection.  You should say Y here if
1568	  you have a multi processor AMD system. This uses an old method to
1569	  read the NUMA configuration directly from the builtin Northbridge
1570	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1571	  which also takes priority if both are compiled in.
1572
1573config X86_64_ACPI_NUMA
1574	def_bool y
1575	prompt "ACPI NUMA detection"
1576	depends on X86_64 && NUMA && ACPI && PCI
1577	select ACPI_NUMA
1578	help
1579	  Enable ACPI SRAT based node topology detection.
1580
1581config NUMA_EMU
1582	bool "NUMA emulation"
1583	depends on NUMA
1584	help
1585	  Enable NUMA emulation. A flat machine will be split
1586	  into virtual nodes when booted with "numa=fake=N", where N is the
1587	  number of nodes. This is only useful for debugging.
1588
1589config NODES_SHIFT
1590	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1591	range 1 10
1592	default "10" if MAXSMP
1593	default "6" if X86_64
1594	default "3"
1595	depends on NUMA
1596	help
1597	  Specify the maximum number of NUMA Nodes available on the target
1598	  system.  Increases memory reserved to accommodate various tables.
1599
1600config ARCH_FLATMEM_ENABLE
1601	def_bool y
1602	depends on X86_32 && !NUMA
1603
1604config ARCH_SPARSEMEM_ENABLE
1605	def_bool y
1606	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1607	select SPARSEMEM_STATIC if X86_32
1608	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1609
1610config ARCH_SPARSEMEM_DEFAULT
1611	def_bool X86_64 || (NUMA && X86_32)
1612
1613config ARCH_SELECT_MEMORY_MODEL
1614	def_bool y
1615	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1616
1617config ARCH_MEMORY_PROBE
1618	bool "Enable sysfs memory/probe interface"
1619	depends on MEMORY_HOTPLUG
1620	help
1621	  This option enables a sysfs memory/probe interface for testing.
1622	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1623	  If you are unsure how to answer this question, answer N.
1624
1625config ARCH_PROC_KCORE_TEXT
1626	def_bool y
1627	depends on X86_64 && PROC_KCORE
1628
1629config ILLEGAL_POINTER_VALUE
1630	hex
1631	default 0 if X86_32
1632	default 0xdead000000000000 if X86_64
1633
1634config X86_PMEM_LEGACY_DEVICE
1635	bool
1636
1637config X86_PMEM_LEGACY
1638	tristate "Support non-standard NVDIMMs and ADR protected memory"
1639	depends on PHYS_ADDR_T_64BIT
1640	depends on BLK_DEV
1641	select X86_PMEM_LEGACY_DEVICE
1642	select NUMA_KEEP_MEMINFO if NUMA
1643	select LIBNVDIMM
1644	help
1645	  Treat memory marked using the non-standard e820 type of 12 as used
1646	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1647	  The kernel will offer these regions to the 'pmem' driver so
1648	  they can be used for persistent storage.
1649
1650	  Say Y if unsure.
1651
1652config HIGHPTE
1653	bool "Allocate 3rd-level pagetables from highmem"
1654	depends on HIGHMEM
1655	help
1656	  The VM uses one page table entry for each page of physical memory.
1657	  For systems with a lot of RAM, this can be wasteful of precious
1658	  low memory.  Setting this option will put user-space page table
1659	  entries in high memory.
1660
1661config X86_CHECK_BIOS_CORRUPTION
1662	bool "Check for low memory corruption"
1663	help
1664	  Periodically check for memory corruption in low memory, which
1665	  is suspected to be caused by BIOS.  Even when enabled in the
1666	  configuration, it is disabled at runtime.  Enable it by
1667	  setting "memory_corruption_check=1" on the kernel command
1668	  line.  By default it scans the low 64k of memory every 60
1669	  seconds; see the memory_corruption_check_size and
1670	  memory_corruption_check_period parameters in
1671	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1672
1673	  When enabled with the default parameters, this option has
1674	  almost no overhead, as it reserves a relatively small amount
1675	  of memory and scans it infrequently.  It both detects corruption
1676	  and prevents it from affecting the running system.
1677
1678	  It is, however, intended as a diagnostic tool; if repeatable
1679	  BIOS-originated corruption always affects the same memory,
1680	  you can use memmap= to prevent the kernel from using that
1681	  memory.
1682
1683config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1684	bool "Set the default setting of memory_corruption_check"
1685	depends on X86_CHECK_BIOS_CORRUPTION
1686	default y
1687	help
1688	  Set whether the default state of memory_corruption_check is
1689	  on or off.
1690
1691config MATH_EMULATION
1692	bool
1693	depends on MODIFY_LDT_SYSCALL
1694	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1695	help
1696	  Linux can emulate a math coprocessor (used for floating point
1697	  operations) if you don't have one. 486DX and Pentium processors have
1698	  a math coprocessor built in, 486SX and 386 do not, unless you added
1699	  a 487DX or 387, respectively. (The messages during boot time can
1700	  give you some hints here ["man dmesg"].) Everyone needs either a
1701	  coprocessor or this emulation.
1702
1703	  If you don't have a math coprocessor, you need to say Y here; if you
1704	  say Y here even though you have a coprocessor, the coprocessor will
1705	  be used nevertheless. (This behavior can be changed with the kernel
1706	  command line option "no387", which comes handy if your coprocessor
1707	  is broken. Try "man bootparam" or see the documentation of your boot
1708	  loader (lilo or loadlin) about how to pass options to the kernel at
1709	  boot time.) This means that it is a good idea to say Y here if you
1710	  intend to use this kernel on different machines.
1711
1712	  More information about the internals of the Linux math coprocessor
1713	  emulation can be found in <file:arch/x86/math-emu/README>.
1714
1715	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1716	  kernel, it won't hurt.
1717
1718config MTRR
1719	def_bool y
1720	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1721	help
1722	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1723	  the Memory Type Range Registers (MTRRs) may be used to control
1724	  processor access to memory ranges. This is most useful if you have
1725	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1726	  allows bus write transfers to be combined into a larger transfer
1727	  before bursting over the PCI/AGP bus. This can increase performance
1728	  of image write operations 2.5 times or more. Saying Y here creates a
1729	  /proc/mtrr file which may be used to manipulate your processor's
1730	  MTRRs. Typically the X server should use this.
1731
1732	  This code has a reasonably generic interface so that similar
1733	  control registers on other processors can be easily supported
1734	  as well:
1735
1736	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1737	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1738	  these, the ARRs are used to emulate the MTRRs.
1739	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1740	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1741	  write-combining. All of these processors are supported by this code
1742	  and it makes sense to say Y here if you have one of them.
1743
1744	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1745	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1746	  can lead to all sorts of problems, so it's good to say Y here.
1747
1748	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1749	  just add about 9 KB to your kernel.
1750
1751	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1752
1753config MTRR_SANITIZER
1754	def_bool y
1755	prompt "MTRR cleanup support"
1756	depends on MTRR
1757	help
1758	  Convert MTRR layout from continuous to discrete, so X drivers can
1759	  add writeback entries.
1760
1761	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1762	  The largest mtrr entry size for a continuous block can be set with
1763	  mtrr_chunk_size.
1764
1765	  If unsure, say Y.
1766
1767config MTRR_SANITIZER_ENABLE_DEFAULT
1768	int "MTRR cleanup enable value (0-1)"
1769	range 0 1
1770	default "0"
1771	depends on MTRR_SANITIZER
1772	help
1773	  Enable mtrr cleanup default value
1774
1775config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1776	int "MTRR cleanup spare reg num (0-7)"
1777	range 0 7
1778	default "1"
1779	depends on MTRR_SANITIZER
1780	help
1781	  mtrr cleanup spare entries default, it can be changed via
1782	  mtrr_spare_reg_nr=N on the kernel command line.
1783
1784config X86_PAT
1785	def_bool y
1786	prompt "x86 PAT support" if EXPERT
1787	depends on MTRR
1788	help
1789	  Use PAT attributes to setup page level cache control.
1790
1791	  PATs are the modern equivalents of MTRRs and are much more
1792	  flexible than MTRRs.
1793
1794	  Say N here if you see bootup problems (boot crash, boot hang,
1795	  spontaneous reboots) or a non-working video driver.
1796
1797	  If unsure, say Y.
1798
1799config ARCH_USES_PG_UNCACHED
1800	def_bool y
1801	depends on X86_PAT
1802
1803config X86_UMIP
1804	def_bool y
1805	prompt "User Mode Instruction Prevention" if EXPERT
1806	help
1807	  User Mode Instruction Prevention (UMIP) is a security feature in
1808	  some x86 processors. If enabled, a general protection fault is
1809	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1810	  executed in user mode. These instructions unnecessarily expose
1811	  information about the hardware state.
1812
1813	  The vast majority of applications do not use these instructions.
1814	  For the very few that do, software emulation is provided in
1815	  specific cases in protected and virtual-8086 modes. Emulated
1816	  results are dummy.
1817
1818config CC_HAS_IBT
1819	# GCC >= 9 and binutils >= 2.29
1820	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1821	# Clang/LLVM >= 14
1822	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1823	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1824	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1825		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1826		  $(as-instr,endbr64)
1827
1828config X86_CET
1829	def_bool n
1830	help
1831	  CET features configured (Shadow stack or IBT)
1832
1833config X86_KERNEL_IBT
1834	prompt "Indirect Branch Tracking"
1835	def_bool y
1836	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1837	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1838	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1839	select OBJTOOL
1840	select X86_CET
1841	help
1842	  Build the kernel with support for Indirect Branch Tracking, a
1843	  hardware support course-grain forward-edge Control Flow Integrity
1844	  protection. It enforces that all indirect calls must land on
1845	  an ENDBR instruction, as such, the compiler will instrument the
1846	  code with them to make this happen.
1847
1848	  In addition to building the kernel with IBT, seal all functions that
1849	  are not indirect call targets, avoiding them ever becoming one.
1850
1851	  This requires LTO like objtool runs and will slow down the build. It
1852	  does significantly reduce the number of ENDBR instructions in the
1853	  kernel image.
1854
1855config X86_INTEL_MEMORY_PROTECTION_KEYS
1856	prompt "Memory Protection Keys"
1857	def_bool y
1858	# Note: only available in 64-bit mode
1859	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1860	select ARCH_USES_HIGH_VMA_FLAGS
1861	select ARCH_HAS_PKEYS
1862	help
1863	  Memory Protection Keys provides a mechanism for enforcing
1864	  page-based protections, but without requiring modification of the
1865	  page tables when an application changes protection domains.
1866
1867	  For details, see Documentation/core-api/protection-keys.rst
1868
1869	  If unsure, say y.
1870
1871choice
1872	prompt "TSX enable mode"
1873	depends on CPU_SUP_INTEL
1874	default X86_INTEL_TSX_MODE_OFF
1875	help
1876	  Intel's TSX (Transactional Synchronization Extensions) feature
1877	  allows to optimize locking protocols through lock elision which
1878	  can lead to a noticeable performance boost.
1879
1880	  On the other hand it has been shown that TSX can be exploited
1881	  to form side channel attacks (e.g. TAA) and chances are there
1882	  will be more of those attacks discovered in the future.
1883
1884	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1885	  might override this decision by tsx=on the command line parameter.
1886	  Even with TSX enabled, the kernel will attempt to enable the best
1887	  possible TAA mitigation setting depending on the microcode available
1888	  for the particular machine.
1889
1890	  This option allows to set the default tsx mode between tsx=on, =off
1891	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1892	  details.
1893
1894	  Say off if not sure, auto if TSX is in use but it should be used on safe
1895	  platforms or on if TSX is in use and the security aspect of tsx is not
1896	  relevant.
1897
1898config X86_INTEL_TSX_MODE_OFF
1899	bool "off"
1900	help
1901	  TSX is disabled if possible - equals to tsx=off command line parameter.
1902
1903config X86_INTEL_TSX_MODE_ON
1904	bool "on"
1905	help
1906	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1907	  line parameter.
1908
1909config X86_INTEL_TSX_MODE_AUTO
1910	bool "auto"
1911	help
1912	  TSX is enabled on TSX capable HW that is believed to be safe against
1913	  side channel attacks- equals the tsx=auto command line parameter.
1914endchoice
1915
1916config X86_SGX
1917	bool "Software Guard eXtensions (SGX)"
1918	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1919	depends on CRYPTO=y
1920	depends on CRYPTO_SHA256=y
1921	select MMU_NOTIFIER
1922	select NUMA_KEEP_MEMINFO if NUMA
1923	select XARRAY_MULTI
1924	help
1925	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1926	  that can be used by applications to set aside private regions of code
1927	  and data, referred to as enclaves. An enclave's private memory can
1928	  only be accessed by code running within the enclave. Accesses from
1929	  outside the enclave, including other enclaves, are disallowed by
1930	  hardware.
1931
1932	  If unsure, say N.
1933
1934config X86_USER_SHADOW_STACK
1935	bool "X86 userspace shadow stack"
1936	depends on AS_WRUSS
1937	depends on X86_64
1938	select ARCH_USES_HIGH_VMA_FLAGS
1939	select X86_CET
1940	help
1941	  Shadow stack protection is a hardware feature that detects function
1942	  return address corruption.  This helps mitigate ROP attacks.
1943	  Applications must be enabled to use it, and old userspace does not
1944	  get protection "for free".
1945
1946	  CPUs supporting shadow stacks were first released in 2020.
1947
1948	  See Documentation/arch/x86/shstk.rst for more information.
1949
1950	  If unsure, say N.
1951
1952config EFI
1953	bool "EFI runtime service support"
1954	depends on ACPI
1955	select UCS2_STRING
1956	select EFI_RUNTIME_WRAPPERS
1957	select ARCH_USE_MEMREMAP_PROT
1958	select EFI_RUNTIME_MAP if KEXEC_CORE
1959	help
1960	  This enables the kernel to use EFI runtime services that are
1961	  available (such as the EFI variable services).
1962
1963	  This option is only useful on systems that have EFI firmware.
1964	  In addition, you should use the latest ELILO loader available
1965	  at <http://elilo.sourceforge.net> in order to take advantage
1966	  of EFI runtime services. However, even with this option, the
1967	  resultant kernel should continue to boot on existing non-EFI
1968	  platforms.
1969
1970config EFI_STUB
1971	bool "EFI stub support"
1972	depends on EFI
1973	select RELOCATABLE
1974	help
1975	  This kernel feature allows a bzImage to be loaded directly
1976	  by EFI firmware without the use of a bootloader.
1977
1978	  See Documentation/admin-guide/efi-stub.rst for more information.
1979
1980config EFI_HANDOVER_PROTOCOL
1981	bool "EFI handover protocol (DEPRECATED)"
1982	depends on EFI_STUB
1983	default y
1984	help
1985	  Select this in order to include support for the deprecated EFI
1986	  handover protocol, which defines alternative entry points into the
1987	  EFI stub.  This is a practice that has no basis in the UEFI
1988	  specification, and requires a priori knowledge on the part of the
1989	  bootloader about Linux/x86 specific ways of passing the command line
1990	  and initrd, and where in memory those assets may be loaded.
1991
1992	  If in doubt, say Y. Even though the corresponding support is not
1993	  present in upstream GRUB or other bootloaders, most distros build
1994	  GRUB with numerous downstream patches applied, and may rely on the
1995	  handover protocol as as result.
1996
1997config EFI_MIXED
1998	bool "EFI mixed-mode support"
1999	depends on EFI_STUB && X86_64
2000	help
2001	  Enabling this feature allows a 64-bit kernel to be booted
2002	  on a 32-bit firmware, provided that your CPU supports 64-bit
2003	  mode.
2004
2005	  Note that it is not possible to boot a mixed-mode enabled
2006	  kernel via the EFI boot stub - a bootloader that supports
2007	  the EFI handover protocol must be used.
2008
2009	  If unsure, say N.
2010
2011config EFI_FAKE_MEMMAP
2012	bool "Enable EFI fake memory map"
2013	depends on EFI
2014	help
2015	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
2016	  this parameter, you can add arbitrary attribute to specific memory
2017	  range by updating original (firmware provided) EFI memmap.  This is
2018	  useful for debugging of EFI memmap related feature, e.g., Address
2019	  Range Mirroring feature.
2020
2021config EFI_MAX_FAKE_MEM
2022	int "maximum allowable number of ranges in efi_fake_mem boot option"
2023	depends on EFI_FAKE_MEMMAP
2024	range 1 128
2025	default 8
2026	help
2027	  Maximum allowable number of ranges in efi_fake_mem boot option.
2028	  Ranges can be set up to this value using comma-separated list.
2029	  The default value is 8.
2030
2031config EFI_RUNTIME_MAP
2032	bool "Export EFI runtime maps to sysfs" if EXPERT
2033	depends on EFI
2034	help
2035	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2036	  That memory map is required by the 2nd kernel to set up EFI virtual
2037	  mappings after kexec, but can also be used for debugging purposes.
2038
2039	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2040
2041source "kernel/Kconfig.hz"
2042
2043config ARCH_SUPPORTS_KEXEC
2044	def_bool y
2045
2046config ARCH_SUPPORTS_KEXEC_FILE
2047	def_bool X86_64
2048
2049config ARCH_SELECTS_KEXEC_FILE
2050	def_bool y
2051	depends on KEXEC_FILE
2052	select HAVE_IMA_KEXEC if IMA
2053
2054config ARCH_SUPPORTS_KEXEC_PURGATORY
2055	def_bool y
2056
2057config ARCH_SUPPORTS_KEXEC_SIG
2058	def_bool y
2059
2060config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2061	def_bool y
2062
2063config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2064	def_bool y
2065
2066config ARCH_SUPPORTS_KEXEC_JUMP
2067	def_bool y
2068
2069config ARCH_SUPPORTS_CRASH_DUMP
2070	def_bool X86_64 || (X86_32 && HIGHMEM)
2071
2072config ARCH_SUPPORTS_CRASH_HOTPLUG
2073	def_bool y
2074
2075config PHYSICAL_START
2076	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2077	default "0x1000000"
2078	help
2079	  This gives the physical address where the kernel is loaded.
2080
2081	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2082	  bzImage will decompress itself to above physical address and
2083	  run from there. Otherwise, bzImage will run from the address where
2084	  it has been loaded by the boot loader and will ignore above physical
2085	  address.
2086
2087	  In normal kdump cases one does not have to set/change this option
2088	  as now bzImage can be compiled as a completely relocatable image
2089	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2090	  address. This option is mainly useful for the folks who don't want
2091	  to use a bzImage for capturing the crash dump and want to use a
2092	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2093	  to be specifically compiled to run from a specific memory area
2094	  (normally a reserved region) and this option comes handy.
2095
2096	  So if you are using bzImage for capturing the crash dump,
2097	  leave the value here unchanged to 0x1000000 and set
2098	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2099	  for capturing the crash dump change this value to start of
2100	  the reserved region.  In other words, it can be set based on
2101	  the "X" value as specified in the "crashkernel=YM@XM"
2102	  command line boot parameter passed to the panic-ed
2103	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2104	  for more details about crash dumps.
2105
2106	  Usage of bzImage for capturing the crash dump is recommended as
2107	  one does not have to build two kernels. Same kernel can be used
2108	  as production kernel and capture kernel. Above option should have
2109	  gone away after relocatable bzImage support is introduced. But it
2110	  is present because there are users out there who continue to use
2111	  vmlinux for dump capture. This option should go away down the
2112	  line.
2113
2114	  Don't change this unless you know what you are doing.
2115
2116config RELOCATABLE
2117	bool "Build a relocatable kernel"
2118	default y
2119	help
2120	  This builds a kernel image that retains relocation information
2121	  so it can be loaded someplace besides the default 1MB.
2122	  The relocations tend to make the kernel binary about 10% larger,
2123	  but are discarded at runtime.
2124
2125	  One use is for the kexec on panic case where the recovery kernel
2126	  must live at a different physical address than the primary
2127	  kernel.
2128
2129	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2130	  it has been loaded at and the compile time physical address
2131	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2132
2133config RANDOMIZE_BASE
2134	bool "Randomize the address of the kernel image (KASLR)"
2135	depends on RELOCATABLE
2136	default y
2137	help
2138	  In support of Kernel Address Space Layout Randomization (KASLR),
2139	  this randomizes the physical address at which the kernel image
2140	  is decompressed and the virtual address where the kernel
2141	  image is mapped, as a security feature that deters exploit
2142	  attempts relying on knowledge of the location of kernel
2143	  code internals.
2144
2145	  On 64-bit, the kernel physical and virtual addresses are
2146	  randomized separately. The physical address will be anywhere
2147	  between 16MB and the top of physical memory (up to 64TB). The
2148	  virtual address will be randomized from 16MB up to 1GB (9 bits
2149	  of entropy). Note that this also reduces the memory space
2150	  available to kernel modules from 1.5GB to 1GB.
2151
2152	  On 32-bit, the kernel physical and virtual addresses are
2153	  randomized together. They will be randomized from 16MB up to
2154	  512MB (8 bits of entropy).
2155
2156	  Entropy is generated using the RDRAND instruction if it is
2157	  supported. If RDTSC is supported, its value is mixed into
2158	  the entropy pool as well. If neither RDRAND nor RDTSC are
2159	  supported, then entropy is read from the i8254 timer. The
2160	  usable entropy is limited by the kernel being built using
2161	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2162	  minimum of 2MB. As a result, only 10 bits of entropy are
2163	  theoretically possible, but the implementations are further
2164	  limited due to memory layouts.
2165
2166	  If unsure, say Y.
2167
2168# Relocation on x86 needs some additional build support
2169config X86_NEED_RELOCS
2170	def_bool y
2171	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2172
2173config PHYSICAL_ALIGN
2174	hex "Alignment value to which kernel should be aligned"
2175	default "0x200000"
2176	range 0x2000 0x1000000 if X86_32
2177	range 0x200000 0x1000000 if X86_64
2178	help
2179	  This value puts the alignment restrictions on physical address
2180	  where kernel is loaded and run from. Kernel is compiled for an
2181	  address which meets above alignment restriction.
2182
2183	  If bootloader loads the kernel at a non-aligned address and
2184	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2185	  address aligned to above value and run from there.
2186
2187	  If bootloader loads the kernel at a non-aligned address and
2188	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2189	  load address and decompress itself to the address it has been
2190	  compiled for and run from there. The address for which kernel is
2191	  compiled already meets above alignment restrictions. Hence the
2192	  end result is that kernel runs from a physical address meeting
2193	  above alignment restrictions.
2194
2195	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2196	  this value must be a multiple of 0x200000.
2197
2198	  Don't change this unless you know what you are doing.
2199
2200config DYNAMIC_MEMORY_LAYOUT
2201	bool
2202	help
2203	  This option makes base addresses of vmalloc and vmemmap as well as
2204	  __PAGE_OFFSET movable during boot.
2205
2206config RANDOMIZE_MEMORY
2207	bool "Randomize the kernel memory sections"
2208	depends on X86_64
2209	depends on RANDOMIZE_BASE
2210	select DYNAMIC_MEMORY_LAYOUT
2211	default RANDOMIZE_BASE
2212	help
2213	  Randomizes the base virtual address of kernel memory sections
2214	  (physical memory mapping, vmalloc & vmemmap). This security feature
2215	  makes exploits relying on predictable memory locations less reliable.
2216
2217	  The order of allocations remains unchanged. Entropy is generated in
2218	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2219	  configuration have in average 30,000 different possible virtual
2220	  addresses for each memory section.
2221
2222	  If unsure, say Y.
2223
2224config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2225	hex "Physical memory mapping padding" if EXPERT
2226	depends on RANDOMIZE_MEMORY
2227	default "0xa" if MEMORY_HOTPLUG
2228	default "0x0"
2229	range 0x1 0x40 if MEMORY_HOTPLUG
2230	range 0x0 0x40
2231	help
2232	  Define the padding in terabytes added to the existing physical
2233	  memory size during kernel memory randomization. It is useful
2234	  for memory hotplug support but reduces the entropy available for
2235	  address randomization.
2236
2237	  If unsure, leave at the default value.
2238
2239config ADDRESS_MASKING
2240	bool "Linear Address Masking support"
2241	depends on X86_64
2242	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2243	help
2244	  Linear Address Masking (LAM) modifies the checking that is applied
2245	  to 64-bit linear addresses, allowing software to use of the
2246	  untranslated address bits for metadata.
2247
2248	  The capability can be used for efficient address sanitizers (ASAN)
2249	  implementation and for optimizations in JITs.
2250
2251config HOTPLUG_CPU
2252	def_bool y
2253	depends on SMP
2254
2255config COMPAT_VDSO
2256	def_bool n
2257	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2258	depends on COMPAT_32
2259	help
2260	  Certain buggy versions of glibc will crash if they are
2261	  presented with a 32-bit vDSO that is not mapped at the address
2262	  indicated in its segment table.
2263
2264	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2265	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2266	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2267	  the only released version with the bug, but OpenSUSE 9
2268	  contains a buggy "glibc 2.3.2".
2269
2270	  The symptom of the bug is that everything crashes on startup, saying:
2271	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2272
2273	  Saying Y here changes the default value of the vdso32 boot
2274	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2275	  This works around the glibc bug but hurts performance.
2276
2277	  If unsure, say N: if you are compiling your own kernel, you
2278	  are unlikely to be using a buggy version of glibc.
2279
2280choice
2281	prompt "vsyscall table for legacy applications"
2282	depends on X86_64
2283	default LEGACY_VSYSCALL_XONLY
2284	help
2285	  Legacy user code that does not know how to find the vDSO expects
2286	  to be able to issue three syscalls by calling fixed addresses in
2287	  kernel space. Since this location is not randomized with ASLR,
2288	  it can be used to assist security vulnerability exploitation.
2289
2290	  This setting can be changed at boot time via the kernel command
2291	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2292	  is deprecated and can only be enabled using the kernel command
2293	  line.
2294
2295	  On a system with recent enough glibc (2.14 or newer) and no
2296	  static binaries, you can say None without a performance penalty
2297	  to improve security.
2298
2299	  If unsure, select "Emulate execution only".
2300
2301	config LEGACY_VSYSCALL_XONLY
2302		bool "Emulate execution only"
2303		help
2304		  The kernel traps and emulates calls into the fixed vsyscall
2305		  address mapping and does not allow reads.  This
2306		  configuration is recommended when userspace might use the
2307		  legacy vsyscall area but support for legacy binary
2308		  instrumentation of legacy code is not needed.  It mitigates
2309		  certain uses of the vsyscall area as an ASLR-bypassing
2310		  buffer.
2311
2312	config LEGACY_VSYSCALL_NONE
2313		bool "None"
2314		help
2315		  There will be no vsyscall mapping at all. This will
2316		  eliminate any risk of ASLR bypass due to the vsyscall
2317		  fixed address mapping. Attempts to use the vsyscalls
2318		  will be reported to dmesg, so that either old or
2319		  malicious userspace programs can be identified.
2320
2321endchoice
2322
2323config CMDLINE_BOOL
2324	bool "Built-in kernel command line"
2325	help
2326	  Allow for specifying boot arguments to the kernel at
2327	  build time.  On some systems (e.g. embedded ones), it is
2328	  necessary or convenient to provide some or all of the
2329	  kernel boot arguments with the kernel itself (that is,
2330	  to not rely on the boot loader to provide them.)
2331
2332	  To compile command line arguments into the kernel,
2333	  set this option to 'Y', then fill in the
2334	  boot arguments in CONFIG_CMDLINE.
2335
2336	  Systems with fully functional boot loaders (i.e. non-embedded)
2337	  should leave this option set to 'N'.
2338
2339config CMDLINE
2340	string "Built-in kernel command string"
2341	depends on CMDLINE_BOOL
2342	default ""
2343	help
2344	  Enter arguments here that should be compiled into the kernel
2345	  image and used at boot time.  If the boot loader provides a
2346	  command line at boot time, it is appended to this string to
2347	  form the full kernel command line, when the system boots.
2348
2349	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2350	  change this behavior.
2351
2352	  In most cases, the command line (whether built-in or provided
2353	  by the boot loader) should specify the device for the root
2354	  file system.
2355
2356config CMDLINE_OVERRIDE
2357	bool "Built-in command line overrides boot loader arguments"
2358	depends on CMDLINE_BOOL && CMDLINE != ""
2359	help
2360	  Set this option to 'Y' to have the kernel ignore the boot loader
2361	  command line, and use ONLY the built-in command line.
2362
2363	  This is used to work around broken boot loaders.  This should
2364	  be set to 'N' under normal conditions.
2365
2366config MODIFY_LDT_SYSCALL
2367	bool "Enable the LDT (local descriptor table)" if EXPERT
2368	default y
2369	help
2370	  Linux can allow user programs to install a per-process x86
2371	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2372	  call.  This is required to run 16-bit or segmented code such as
2373	  DOSEMU or some Wine programs.  It is also used by some very old
2374	  threading libraries.
2375
2376	  Enabling this feature adds a small amount of overhead to
2377	  context switches and increases the low-level kernel attack
2378	  surface.  Disabling it removes the modify_ldt(2) system call.
2379
2380	  Saying 'N' here may make sense for embedded or server kernels.
2381
2382config STRICT_SIGALTSTACK_SIZE
2383	bool "Enforce strict size checking for sigaltstack"
2384	depends on DYNAMIC_SIGFRAME
2385	help
2386	  For historical reasons MINSIGSTKSZ is a constant which became
2387	  already too small with AVX512 support. Add a mechanism to
2388	  enforce strict checking of the sigaltstack size against the
2389	  real size of the FPU frame. This option enables the check
2390	  by default. It can also be controlled via the kernel command
2391	  line option 'strict_sas_size' independent of this config
2392	  switch. Enabling it might break existing applications which
2393	  allocate a too small sigaltstack but 'work' because they
2394	  never get a signal delivered.
2395
2396	  Say 'N' unless you want to really enforce this check.
2397
2398source "kernel/livepatch/Kconfig"
2399
2400endmenu
2401
2402config CC_HAS_SLS
2403	def_bool $(cc-option,-mharden-sls=all)
2404
2405config CC_HAS_RETURN_THUNK
2406	def_bool $(cc-option,-mfunction-return=thunk-extern)
2407
2408config CC_HAS_ENTRY_PADDING
2409	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2410
2411config FUNCTION_PADDING_CFI
2412	int
2413	default 59 if FUNCTION_ALIGNMENT_64B
2414	default 27 if FUNCTION_ALIGNMENT_32B
2415	default 11 if FUNCTION_ALIGNMENT_16B
2416	default  3 if FUNCTION_ALIGNMENT_8B
2417	default  0
2418
2419# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2420# except Kconfig can't do arithmetic :/
2421config FUNCTION_PADDING_BYTES
2422	int
2423	default FUNCTION_PADDING_CFI if CFI_CLANG
2424	default FUNCTION_ALIGNMENT
2425
2426config CALL_PADDING
2427	def_bool n
2428	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2429	select FUNCTION_ALIGNMENT_16B
2430
2431config FINEIBT
2432	def_bool y
2433	depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE
2434	select CALL_PADDING
2435
2436config HAVE_CALL_THUNKS
2437	def_bool y
2438	depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
2439
2440config CALL_THUNKS
2441	def_bool n
2442	select CALL_PADDING
2443
2444config PREFIX_SYMBOLS
2445	def_bool y
2446	depends on CALL_PADDING && !CFI_CLANG
2447
2448menuconfig CPU_MITIGATIONS
2449	bool "Mitigations for CPU vulnerabilities"
2450	default y
2451	help
2452	  Say Y here to enable options which enable mitigations for hardware
2453	  vulnerabilities (usually related to speculative execution).
2454	  Mitigations can be disabled or restricted to SMT systems at runtime
2455	  via the "mitigations" kernel parameter.
2456
2457	  If you say N, all mitigations will be disabled.  This CANNOT be
2458	  overridden at runtime.
2459
2460	  Say 'Y', unless you really know what you are doing.
2461
2462if CPU_MITIGATIONS
2463
2464config PAGE_TABLE_ISOLATION
2465	bool "Remove the kernel mapping in user mode"
2466	default y
2467	depends on (X86_64 || X86_PAE)
2468	help
2469	  This feature reduces the number of hardware side channels by
2470	  ensuring that the majority of kernel addresses are not mapped
2471	  into userspace.
2472
2473	  See Documentation/arch/x86/pti.rst for more details.
2474
2475config RETPOLINE
2476	bool "Avoid speculative indirect branches in kernel"
2477	select OBJTOOL if HAVE_OBJTOOL
2478	default y
2479	help
2480	  Compile kernel with the retpoline compiler options to guard against
2481	  kernel-to-user data leaks by avoiding speculative indirect
2482	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2483	  support for full protection. The kernel may run slower.
2484
2485config RETHUNK
2486	bool "Enable return-thunks"
2487	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2488	select OBJTOOL if HAVE_OBJTOOL
2489	default y if X86_64
2490	help
2491	  Compile the kernel with the return-thunks compiler option to guard
2492	  against kernel-to-user data leaks by avoiding return speculation.
2493	  Requires a compiler with -mfunction-return=thunk-extern
2494	  support for full protection. The kernel may run slower.
2495
2496config CPU_UNRET_ENTRY
2497	bool "Enable UNRET on kernel entry"
2498	depends on CPU_SUP_AMD && RETHUNK && X86_64
2499	default y
2500	help
2501	  Compile the kernel with support for the retbleed=unret mitigation.
2502
2503config CALL_DEPTH_TRACKING
2504	bool "Mitigate RSB underflow with call depth tracking"
2505	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2506	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2507	select CALL_THUNKS
2508	default y
2509	help
2510	  Compile the kernel with call depth tracking to mitigate the Intel
2511	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
2512	  mitigation is off by default and needs to be enabled on the
2513	  kernel command line via the retbleed=stuff option. For
2514	  non-affected systems the overhead of this option is marginal as
2515	  the call depth tracking is using run-time generated call thunks
2516	  in a compiler generated padding area and call patching. This
2517	  increases text size by ~5%. For non affected systems this space
2518	  is unused. On affected SKL systems this results in a significant
2519	  performance gain over the IBRS mitigation.
2520
2521config CALL_THUNKS_DEBUG
2522	bool "Enable call thunks and call depth tracking debugging"
2523	depends on CALL_DEPTH_TRACKING
2524	select FUNCTION_ALIGNMENT_32B
2525	default n
2526	help
2527	  Enable call/ret counters for imbalance detection and build in
2528	  a noisy dmesg about callthunks generation and call patching for
2529	  trouble shooting. The debug prints need to be enabled on the
2530	  kernel command line with 'debug-callthunks'.
2531	  Only enable this when you are debugging call thunks as this
2532	  creates a noticeable runtime overhead. If unsure say N.
2533
2534config CPU_IBPB_ENTRY
2535	bool "Enable IBPB on kernel entry"
2536	depends on CPU_SUP_AMD && X86_64
2537	default y
2538	help
2539	  Compile the kernel with support for the retbleed=ibpb and
2540	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2541
2542config CPU_IBRS_ENTRY
2543	bool "Enable IBRS on kernel entry"
2544	depends on CPU_SUP_INTEL && X86_64
2545	default y
2546	help
2547	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2548	  This mitigates both spectre_v2 and retbleed at great cost to
2549	  performance.
2550
2551config CPU_SRSO
2552	bool "Mitigate speculative RAS overflow on AMD"
2553	depends on CPU_SUP_AMD && X86_64 && RETHUNK
2554	default y
2555	help
2556	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2557
2558config SLS
2559	bool "Mitigate Straight-Line-Speculation"
2560	depends on CC_HAS_SLS && X86_64
2561	select OBJTOOL if HAVE_OBJTOOL
2562	default n
2563	help
2564	  Compile the kernel with straight-line-speculation options to guard
2565	  against straight line speculation. The kernel image might be slightly
2566	  larger.
2567
2568config GDS_FORCE_MITIGATION
2569	bool "Force GDS Mitigation"
2570	depends on CPU_SUP_INTEL
2571	default n
2572	help
2573	  Gather Data Sampling (GDS) is a hardware vulnerability which allows
2574	  unprivileged speculative access to data which was previously stored in
2575	  vector registers.
2576
2577	  This option is equivalent to setting gather_data_sampling=force on the
2578	  command line. The microcode mitigation is used if present, otherwise
2579	  AVX is disabled as a mitigation. On affected systems that are missing
2580	  the microcode any userspace code that unconditionally uses AVX will
2581	  break with this option set.
2582
2583	  Setting this option on systems not vulnerable to GDS has no effect.
2584
2585	  If in doubt, say N.
2586
2587config MITIGATION_RFDS
2588	bool "RFDS Mitigation"
2589	depends on CPU_SUP_INTEL
2590	default y
2591	help
2592	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2593	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2594	  allows unprivileged speculative access to stale data previously
2595	  stored in floating point, vector and integer registers.
2596	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2597
2598config MITIGATION_SPECTRE_BHI
2599	bool "Mitigate Spectre-BHB (Branch History Injection)"
2600	depends on CPU_SUP_INTEL
2601	default y
2602	help
2603	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2604	  where the branch history buffer is poisoned to speculatively steer
2605	  indirect branches.
2606	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2607
2608endif
2609
2610config ARCH_HAS_ADD_PAGES
2611	def_bool y
2612	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2613
2614menu "Power management and ACPI options"
2615
2616config ARCH_HIBERNATION_HEADER
2617	def_bool y
2618	depends on HIBERNATION
2619
2620source "kernel/power/Kconfig"
2621
2622source "drivers/acpi/Kconfig"
2623
2624config X86_APM_BOOT
2625	def_bool y
2626	depends on APM
2627
2628menuconfig APM
2629	tristate "APM (Advanced Power Management) BIOS support"
2630	depends on X86_32 && PM_SLEEP
2631	help
2632	  APM is a BIOS specification for saving power using several different
2633	  techniques. This is mostly useful for battery powered laptops with
2634	  APM compliant BIOSes. If you say Y here, the system time will be
2635	  reset after a RESUME operation, the /proc/apm device will provide
2636	  battery status information, and user-space programs will receive
2637	  notification of APM "events" (e.g. battery status change).
2638
2639	  If you select "Y" here, you can disable actual use of the APM
2640	  BIOS by passing the "apm=off" option to the kernel at boot time.
2641
2642	  Note that the APM support is almost completely disabled for
2643	  machines with more than one CPU.
2644
2645	  In order to use APM, you will need supporting software. For location
2646	  and more information, read <file:Documentation/power/apm-acpi.rst>
2647	  and the Battery Powered Linux mini-HOWTO, available from
2648	  <http://www.tldp.org/docs.html#howto>.
2649
2650	  This driver does not spin down disk drives (see the hdparm(8)
2651	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2652	  VESA-compliant "green" monitors.
2653
2654	  This driver does not support the TI 4000M TravelMate and the ACER
2655	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2656	  desktop machines also don't have compliant BIOSes, and this driver
2657	  may cause those machines to panic during the boot phase.
2658
2659	  Generally, if you don't have a battery in your machine, there isn't
2660	  much point in using this driver and you should say N. If you get
2661	  random kernel OOPSes or reboots that don't seem to be related to
2662	  anything, try disabling/enabling this option (or disabling/enabling
2663	  APM in your BIOS).
2664
2665	  Some other things you should try when experiencing seemingly random,
2666	  "weird" problems:
2667
2668	  1) make sure that you have enough swap space and that it is
2669	  enabled.
2670	  2) pass the "idle=poll" option to the kernel
2671	  3) switch on floating point emulation in the kernel and pass
2672	  the "no387" option to the kernel
2673	  4) pass the "floppy=nodma" option to the kernel
2674	  5) pass the "mem=4M" option to the kernel (thereby disabling
2675	  all but the first 4 MB of RAM)
2676	  6) make sure that the CPU is not over clocked.
2677	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2678	  8) disable the cache from your BIOS settings
2679	  9) install a fan for the video card or exchange video RAM
2680	  10) install a better fan for the CPU
2681	  11) exchange RAM chips
2682	  12) exchange the motherboard.
2683
2684	  To compile this driver as a module, choose M here: the
2685	  module will be called apm.
2686
2687if APM
2688
2689config APM_IGNORE_USER_SUSPEND
2690	bool "Ignore USER SUSPEND"
2691	help
2692	  This option will ignore USER SUSPEND requests. On machines with a
2693	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2694	  series notebooks, it is necessary to say Y because of a BIOS bug.
2695
2696config APM_DO_ENABLE
2697	bool "Enable PM at boot time"
2698	help
2699	  Enable APM features at boot time. From page 36 of the APM BIOS
2700	  specification: "When disabled, the APM BIOS does not automatically
2701	  power manage devices, enter the Standby State, enter the Suspend
2702	  State, or take power saving steps in response to CPU Idle calls."
2703	  This driver will make CPU Idle calls when Linux is idle (unless this
2704	  feature is turned off -- see "Do CPU IDLE calls", below). This
2705	  should always save battery power, but more complicated APM features
2706	  will be dependent on your BIOS implementation. You may need to turn
2707	  this option off if your computer hangs at boot time when using APM
2708	  support, or if it beeps continuously instead of suspending. Turn
2709	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2710	  T400CDT. This is off by default since most machines do fine without
2711	  this feature.
2712
2713config APM_CPU_IDLE
2714	depends on CPU_IDLE
2715	bool "Make CPU Idle calls when idle"
2716	help
2717	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2718	  On some machines, this can activate improved power savings, such as
2719	  a slowed CPU clock rate, when the machine is idle. These idle calls
2720	  are made after the idle loop has run for some length of time (e.g.,
2721	  333 mS). On some machines, this will cause a hang at boot time or
2722	  whenever the CPU becomes idle. (On machines with more than one CPU,
2723	  this option does nothing.)
2724
2725config APM_DISPLAY_BLANK
2726	bool "Enable console blanking using APM"
2727	help
2728	  Enable console blanking using the APM. Some laptops can use this to
2729	  turn off the LCD backlight when the screen blanker of the Linux
2730	  virtual console blanks the screen. Note that this is only used by
2731	  the virtual console screen blanker, and won't turn off the backlight
2732	  when using the X Window system. This also doesn't have anything to
2733	  do with your VESA-compliant power-saving monitor. Further, this
2734	  option doesn't work for all laptops -- it might not turn off your
2735	  backlight at all, or it might print a lot of errors to the console,
2736	  especially if you are using gpm.
2737
2738config APM_ALLOW_INTS
2739	bool "Allow interrupts during APM BIOS calls"
2740	help
2741	  Normally we disable external interrupts while we are making calls to
2742	  the APM BIOS as a measure to lessen the effects of a badly behaving
2743	  BIOS implementation.  The BIOS should reenable interrupts if it
2744	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2745	  many of the newer IBM Thinkpads.  If you experience hangs when you
2746	  suspend, try setting this to Y.  Otherwise, say N.
2747
2748endif # APM
2749
2750source "drivers/cpufreq/Kconfig"
2751
2752source "drivers/cpuidle/Kconfig"
2753
2754source "drivers/idle/Kconfig"
2755
2756endmenu
2757
2758menu "Bus options (PCI etc.)"
2759
2760choice
2761	prompt "PCI access mode"
2762	depends on X86_32 && PCI
2763	default PCI_GOANY
2764	help
2765	  On PCI systems, the BIOS can be used to detect the PCI devices and
2766	  determine their configuration. However, some old PCI motherboards
2767	  have BIOS bugs and may crash if this is done. Also, some embedded
2768	  PCI-based systems don't have any BIOS at all. Linux can also try to
2769	  detect the PCI hardware directly without using the BIOS.
2770
2771	  With this option, you can specify how Linux should detect the
2772	  PCI devices. If you choose "BIOS", the BIOS will be used,
2773	  if you choose "Direct", the BIOS won't be used, and if you
2774	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2775	  If you choose "Any", the kernel will try MMCONFIG, then the
2776	  direct access method and falls back to the BIOS if that doesn't
2777	  work. If unsure, go with the default, which is "Any".
2778
2779config PCI_GOBIOS
2780	bool "BIOS"
2781
2782config PCI_GOMMCONFIG
2783	bool "MMConfig"
2784
2785config PCI_GODIRECT
2786	bool "Direct"
2787
2788config PCI_GOOLPC
2789	bool "OLPC XO-1"
2790	depends on OLPC
2791
2792config PCI_GOANY
2793	bool "Any"
2794
2795endchoice
2796
2797config PCI_BIOS
2798	def_bool y
2799	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2800
2801# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2802config PCI_DIRECT
2803	def_bool y
2804	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2805
2806config PCI_MMCONFIG
2807	bool "Support mmconfig PCI config space access" if X86_64
2808	default y
2809	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2810	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2811
2812config PCI_OLPC
2813	def_bool y
2814	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2815
2816config PCI_XEN
2817	def_bool y
2818	depends on PCI && XEN
2819
2820config MMCONF_FAM10H
2821	def_bool y
2822	depends on X86_64 && PCI_MMCONFIG && ACPI
2823
2824config PCI_CNB20LE_QUIRK
2825	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2826	depends on PCI
2827	help
2828	  Read the PCI windows out of the CNB20LE host bridge. This allows
2829	  PCI hotplug to work on systems with the CNB20LE chipset which do
2830	  not have ACPI.
2831
2832	  There's no public spec for this chipset, and this functionality
2833	  is known to be incomplete.
2834
2835	  You should say N unless you know you need this.
2836
2837config ISA_BUS
2838	bool "ISA bus support on modern systems" if EXPERT
2839	help
2840	  Expose ISA bus device drivers and options available for selection and
2841	  configuration. Enable this option if your target machine has an ISA
2842	  bus. ISA is an older system, displaced by PCI and newer bus
2843	  architectures -- if your target machine is modern, it probably does
2844	  not have an ISA bus.
2845
2846	  If unsure, say N.
2847
2848# x86_64 have no ISA slots, but can have ISA-style DMA.
2849config ISA_DMA_API
2850	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2851	default y
2852	help
2853	  Enables ISA-style DMA support for devices requiring such controllers.
2854	  If unsure, say Y.
2855
2856if X86_32
2857
2858config ISA
2859	bool "ISA support"
2860	help
2861	  Find out whether you have ISA slots on your motherboard.  ISA is the
2862	  name of a bus system, i.e. the way the CPU talks to the other stuff
2863	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2864	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2865	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2866
2867config SCx200
2868	tristate "NatSemi SCx200 support"
2869	help
2870	  This provides basic support for National Semiconductor's
2871	  (now AMD's) Geode processors.  The driver probes for the
2872	  PCI-IDs of several on-chip devices, so its a good dependency
2873	  for other scx200_* drivers.
2874
2875	  If compiled as a module, the driver is named scx200.
2876
2877config SCx200HR_TIMER
2878	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2879	depends on SCx200
2880	default y
2881	help
2882	  This driver provides a clocksource built upon the on-chip
2883	  27MHz high-resolution timer.  Its also a workaround for
2884	  NSC Geode SC-1100's buggy TSC, which loses time when the
2885	  processor goes idle (as is done by the scheduler).  The
2886	  other workaround is idle=poll boot option.
2887
2888config OLPC
2889	bool "One Laptop Per Child support"
2890	depends on !X86_PAE
2891	select GPIOLIB
2892	select OF
2893	select OF_PROMTREE
2894	select IRQ_DOMAIN
2895	select OLPC_EC
2896	help
2897	  Add support for detecting the unique features of the OLPC
2898	  XO hardware.
2899
2900config OLPC_XO1_PM
2901	bool "OLPC XO-1 Power Management"
2902	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2903	help
2904	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2905
2906config OLPC_XO1_RTC
2907	bool "OLPC XO-1 Real Time Clock"
2908	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2909	help
2910	  Add support for the XO-1 real time clock, which can be used as a
2911	  programmable wakeup source.
2912
2913config OLPC_XO1_SCI
2914	bool "OLPC XO-1 SCI extras"
2915	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2916	depends on INPUT=y
2917	select POWER_SUPPLY
2918	help
2919	  Add support for SCI-based features of the OLPC XO-1 laptop:
2920	   - EC-driven system wakeups
2921	   - Power button
2922	   - Ebook switch
2923	   - Lid switch
2924	   - AC adapter status updates
2925	   - Battery status updates
2926
2927config OLPC_XO15_SCI
2928	bool "OLPC XO-1.5 SCI extras"
2929	depends on OLPC && ACPI
2930	select POWER_SUPPLY
2931	help
2932	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2933	   - EC-driven system wakeups
2934	   - AC adapter status updates
2935	   - Battery status updates
2936
2937config ALIX
2938	bool "PCEngines ALIX System Support (LED setup)"
2939	select GPIOLIB
2940	help
2941	  This option enables system support for the PCEngines ALIX.
2942	  At present this just sets up LEDs for GPIO control on
2943	  ALIX2/3/6 boards.  However, other system specific setup should
2944	  get added here.
2945
2946	  Note: You must still enable the drivers for GPIO and LED support
2947	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2948
2949	  Note: You have to set alix.force=1 for boards with Award BIOS.
2950
2951config NET5501
2952	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2953	select GPIOLIB
2954	help
2955	  This option enables system support for the Soekris Engineering net5501.
2956
2957config GEOS
2958	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2959	select GPIOLIB
2960	depends on DMI
2961	help
2962	  This option enables system support for the Traverse Technologies GEOS.
2963
2964config TS5500
2965	bool "Technologic Systems TS-5500 platform support"
2966	depends on MELAN
2967	select CHECK_SIGNATURE
2968	select NEW_LEDS
2969	select LEDS_CLASS
2970	help
2971	  This option enables system support for the Technologic Systems TS-5500.
2972
2973endif # X86_32
2974
2975config AMD_NB
2976	def_bool y
2977	depends on CPU_SUP_AMD && PCI
2978
2979endmenu
2980
2981menu "Binary Emulations"
2982
2983config IA32_EMULATION
2984	bool "IA32 Emulation"
2985	depends on X86_64
2986	select ARCH_WANT_OLD_COMPAT_IPC
2987	select BINFMT_ELF
2988	select COMPAT_OLD_SIGACTION
2989	help
2990	  Include code to run legacy 32-bit programs under a
2991	  64-bit kernel. You should likely turn this on, unless you're
2992	  100% sure that you don't have any 32-bit programs left.
2993
2994config X86_X32_ABI
2995	bool "x32 ABI for 64-bit mode"
2996	depends on X86_64
2997	# llvm-objcopy does not convert x86_64 .note.gnu.property or
2998	# compressed debug sections to x86_x32 properly:
2999	# https://github.com/ClangBuiltLinux/linux/issues/514
3000	# https://github.com/ClangBuiltLinux/linux/issues/1141
3001	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3002	help
3003	  Include code to run binaries for the x32 native 32-bit ABI
3004	  for 64-bit processors.  An x32 process gets access to the
3005	  full 64-bit register file and wide data path while leaving
3006	  pointers at 32 bits for smaller memory footprint.
3007
3008config COMPAT_32
3009	def_bool y
3010	depends on IA32_EMULATION || X86_32
3011	select HAVE_UID16
3012	select OLD_SIGSUSPEND3
3013
3014config COMPAT
3015	def_bool y
3016	depends on IA32_EMULATION || X86_X32_ABI
3017
3018config COMPAT_FOR_U64_ALIGNMENT
3019	def_bool y
3020	depends on COMPAT
3021
3022endmenu
3023
3024config HAVE_ATOMIC_IOMAP
3025	def_bool y
3026	depends on X86_32
3027
3028source "arch/x86/kvm/Kconfig"
3029
3030source "arch/x86/Kconfig.assembler"
3031