xref: /openbmc/linux/arch/x86/Kconfig (revision d699090510c3223641a23834b4710e2d4309a6ad)
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			if X86_32
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	depends on PARAVIRT
885	select ARCH_HAS_CC_PLATFORM
886	select X86_MEM_ENCRYPT
887	select X86_MCE
888	select UNACCEPTED_MEMORY
889	help
890	  Support running as a guest under Intel TDX.  Without this support,
891	  the guest kernel can not boot or run under TDX.
892	  TDX includes memory encryption and integrity capabilities
893	  which protect the confidentiality and integrity of guest
894	  memory contents and CPU state. TDX guests are protected from
895	  some attacks from the VMM.
896
897endif # HYPERVISOR_GUEST
898
899source "arch/x86/Kconfig.cpu"
900
901config HPET_TIMER
902	def_bool X86_64
903	prompt "HPET Timer Support" if X86_32
904	help
905	  Use the IA-PC HPET (High Precision Event Timer) to manage
906	  time in preference to the PIT and RTC, if a HPET is
907	  present.
908	  HPET is the next generation timer replacing legacy 8254s.
909	  The HPET provides a stable time base on SMP
910	  systems, unlike the TSC, but it is more expensive to access,
911	  as it is off-chip.  The interface used is documented
912	  in the HPET spec, revision 1.
913
914	  You can safely choose Y here.  However, HPET will only be
915	  activated if the platform and the BIOS support this feature.
916	  Otherwise the 8254 will be used for timing services.
917
918	  Choose N to continue using the legacy 8254 timer.
919
920config HPET_EMULATE_RTC
921	def_bool y
922	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
923
924# Mark as expert because too many people got it wrong.
925# The code disables itself when not needed.
926config DMI
927	default y
928	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
929	bool "Enable DMI scanning" if EXPERT
930	help
931	  Enabled scanning of DMI to identify machine quirks. Say Y
932	  here unless you have verified that your setup is not
933	  affected by entries in the DMI blacklist. Required by PNP
934	  BIOS code.
935
936config GART_IOMMU
937	bool "Old AMD GART IOMMU support"
938	select DMA_OPS
939	select IOMMU_HELPER
940	select SWIOTLB
941	depends on X86_64 && PCI && AMD_NB
942	help
943	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
944	  GART based hardware IOMMUs.
945
946	  The GART supports full DMA access for devices with 32-bit access
947	  limitations, on systems with more than 3 GB. This is usually needed
948	  for USB, sound, many IDE/SATA chipsets and some other devices.
949
950	  Newer systems typically have a modern AMD IOMMU, supported via
951	  the CONFIG_AMD_IOMMU=y config option.
952
953	  In normal configurations this driver is only active when needed:
954	  there's more than 3 GB of memory and the system contains a
955	  32-bit limited device.
956
957	  If unsure, say Y.
958
959config BOOT_VESA_SUPPORT
960	bool
961	help
962	  If true, at least one selected framebuffer driver can take advantage
963	  of VESA video modes set at an early boot stage via the vga= parameter.
964
965config MAXSMP
966	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
967	depends on X86_64 && SMP && DEBUG_KERNEL
968	select CPUMASK_OFFSTACK
969	help
970	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
971	  If unsure, say N.
972
973#
974# The maximum number of CPUs supported:
975#
976# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
977# and which can be configured interactively in the
978# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
979#
980# The ranges are different on 32-bit and 64-bit kernels, depending on
981# hardware capabilities and scalability features of the kernel.
982#
983# ( If MAXSMP is enabled we just use the highest possible value and disable
984#   interactive configuration. )
985#
986
987config NR_CPUS_RANGE_BEGIN
988	int
989	default NR_CPUS_RANGE_END if MAXSMP
990	default    1 if !SMP
991	default    2
992
993config NR_CPUS_RANGE_END
994	int
995	depends on X86_32
996	default   64 if  SMP &&  X86_BIGSMP
997	default    8 if  SMP && !X86_BIGSMP
998	default    1 if !SMP
999
1000config NR_CPUS_RANGE_END
1001	int
1002	depends on X86_64
1003	default 8192 if  SMP && CPUMASK_OFFSTACK
1004	default  512 if  SMP && !CPUMASK_OFFSTACK
1005	default    1 if !SMP
1006
1007config NR_CPUS_DEFAULT
1008	int
1009	depends on X86_32
1010	default   32 if  X86_BIGSMP
1011	default    8 if  SMP
1012	default    1 if !SMP
1013
1014config NR_CPUS_DEFAULT
1015	int
1016	depends on X86_64
1017	default 8192 if  MAXSMP
1018	default   64 if  SMP
1019	default    1 if !SMP
1020
1021config NR_CPUS
1022	int "Maximum number of CPUs" if SMP && !MAXSMP
1023	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1024	default NR_CPUS_DEFAULT
1025	help
1026	  This allows you to specify the maximum number of CPUs which this
1027	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1028	  supported value is 8192, otherwise the maximum value is 512.  The
1029	  minimum value which makes sense is 2.
1030
1031	  This is purely to save memory: each supported CPU adds about 8KB
1032	  to the kernel image.
1033
1034config SCHED_CLUSTER
1035	bool "Cluster scheduler support"
1036	depends on SMP
1037	default y
1038	help
1039	  Cluster scheduler support improves the CPU scheduler's decision
1040	  making when dealing with machines that have clusters of CPUs.
1041	  Cluster usually means a couple of CPUs which are placed closely
1042	  by sharing mid-level caches, last-level cache tags or internal
1043	  busses.
1044
1045config SCHED_SMT
1046	def_bool y if SMP
1047
1048config SCHED_MC
1049	def_bool y
1050	prompt "Multi-core scheduler support"
1051	depends on SMP
1052	help
1053	  Multi-core scheduler support improves the CPU scheduler's decision
1054	  making when dealing with multi-core CPU chips at a cost of slightly
1055	  increased overhead in some places. If unsure say N here.
1056
1057config SCHED_MC_PRIO
1058	bool "CPU core priorities scheduler support"
1059	depends on SCHED_MC && CPU_SUP_INTEL
1060	select X86_INTEL_PSTATE
1061	select CPU_FREQ
1062	default y
1063	help
1064	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1065	  core ordering determined at manufacturing time, which allows
1066	  certain cores to reach higher turbo frequencies (when running
1067	  single threaded workloads) than others.
1068
1069	  Enabling this kernel feature teaches the scheduler about
1070	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1071	  scheduler's CPU selection logic accordingly, so that higher
1072	  overall system performance can be achieved.
1073
1074	  This feature will have no effect on CPUs without this feature.
1075
1076	  If unsure say Y here.
1077
1078config UP_LATE_INIT
1079	def_bool y
1080	depends on !SMP && X86_LOCAL_APIC
1081
1082config X86_UP_APIC
1083	bool "Local APIC support on uniprocessors" if !PCI_MSI
1084	default PCI_MSI
1085	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1086	help
1087	  A local APIC (Advanced Programmable Interrupt Controller) is an
1088	  integrated interrupt controller in the CPU. If you have a single-CPU
1089	  system which has a processor with a local APIC, you can say Y here to
1090	  enable and use it. If you say Y here even though your machine doesn't
1091	  have a local APIC, then the kernel will still run with no slowdown at
1092	  all. The local APIC supports CPU-generated self-interrupts (timer,
1093	  performance counters), and the NMI watchdog which detects hard
1094	  lockups.
1095
1096config X86_UP_IOAPIC
1097	bool "IO-APIC support on uniprocessors"
1098	depends on X86_UP_APIC
1099	help
1100	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1101	  SMP-capable replacement for PC-style interrupt controllers. Most
1102	  SMP systems and many recent uniprocessor systems have one.
1103
1104	  If you have a single-CPU system with an IO-APIC, you can say Y here
1105	  to use it. If you say Y here even though your machine doesn't have
1106	  an IO-APIC, then the kernel will still run with no slowdown at all.
1107
1108config X86_LOCAL_APIC
1109	def_bool y
1110	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1111	select IRQ_DOMAIN_HIERARCHY
1112
1113config X86_IO_APIC
1114	def_bool y
1115	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1116
1117config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1118	bool "Reroute for broken boot IRQs"
1119	depends on X86_IO_APIC
1120	help
1121	  This option enables a workaround that fixes a source of
1122	  spurious interrupts. This is recommended when threaded
1123	  interrupt handling is used on systems where the generation of
1124	  superfluous "boot interrupts" cannot be disabled.
1125
1126	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1127	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1128	  kernel does during interrupt handling). On chipsets where this
1129	  boot IRQ generation cannot be disabled, this workaround keeps
1130	  the original IRQ line masked so that only the equivalent "boot
1131	  IRQ" is delivered to the CPUs. The workaround also tells the
1132	  kernel to set up the IRQ handler on the boot IRQ line. In this
1133	  way only one interrupt is delivered to the kernel. Otherwise
1134	  the spurious second interrupt may cause the kernel to bring
1135	  down (vital) interrupt lines.
1136
1137	  Only affects "broken" chipsets. Interrupt sharing may be
1138	  increased on these systems.
1139
1140config X86_MCE
1141	bool "Machine Check / overheating reporting"
1142	select GENERIC_ALLOCATOR
1143	default y
1144	help
1145	  Machine Check support allows the processor to notify the
1146	  kernel if it detects a problem (e.g. overheating, data corruption).
1147	  The action the kernel takes depends on the severity of the problem,
1148	  ranging from warning messages to halting the machine.
1149
1150config X86_MCELOG_LEGACY
1151	bool "Support for deprecated /dev/mcelog character device"
1152	depends on X86_MCE
1153	help
1154	  Enable support for /dev/mcelog which is needed by the old mcelog
1155	  userspace logging daemon. Consider switching to the new generation
1156	  rasdaemon solution.
1157
1158config X86_MCE_INTEL
1159	def_bool y
1160	prompt "Intel MCE features"
1161	depends on X86_MCE && X86_LOCAL_APIC
1162	help
1163	  Additional support for intel specific MCE features such as
1164	  the thermal monitor.
1165
1166config X86_MCE_AMD
1167	def_bool y
1168	prompt "AMD MCE features"
1169	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1170	help
1171	  Additional support for AMD specific MCE features such as
1172	  the DRAM Error Threshold.
1173
1174config X86_ANCIENT_MCE
1175	bool "Support for old Pentium 5 / WinChip machine checks"
1176	depends on X86_32 && X86_MCE
1177	help
1178	  Include support for machine check handling on old Pentium 5 or WinChip
1179	  systems. These typically need to be enabled explicitly on the command
1180	  line.
1181
1182config X86_MCE_THRESHOLD
1183	depends on X86_MCE_AMD || X86_MCE_INTEL
1184	def_bool y
1185
1186config X86_MCE_INJECT
1187	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1188	tristate "Machine check injector support"
1189	help
1190	  Provide support for injecting machine checks for testing purposes.
1191	  If you don't know what a machine check is and you don't do kernel
1192	  QA it is safe to say n.
1193
1194source "arch/x86/events/Kconfig"
1195
1196config X86_LEGACY_VM86
1197	bool "Legacy VM86 support"
1198	depends on X86_32
1199	help
1200	  This option allows user programs to put the CPU into V8086
1201	  mode, which is an 80286-era approximation of 16-bit real mode.
1202
1203	  Some very old versions of X and/or vbetool require this option
1204	  for user mode setting.  Similarly, DOSEMU will use it if
1205	  available to accelerate real mode DOS programs.  However, any
1206	  recent version of DOSEMU, X, or vbetool should be fully
1207	  functional even without kernel VM86 support, as they will all
1208	  fall back to software emulation. Nevertheless, if you are using
1209	  a 16-bit DOS program where 16-bit performance matters, vm86
1210	  mode might be faster than emulation and you might want to
1211	  enable this option.
1212
1213	  Note that any app that works on a 64-bit kernel is unlikely to
1214	  need this option, as 64-bit kernels don't, and can't, support
1215	  V8086 mode. This option is also unrelated to 16-bit protected
1216	  mode and is not needed to run most 16-bit programs under Wine.
1217
1218	  Enabling this option increases the complexity of the kernel
1219	  and slows down exception handling a tiny bit.
1220
1221	  If unsure, say N here.
1222
1223config VM86
1224	bool
1225	default X86_LEGACY_VM86
1226
1227config X86_16BIT
1228	bool "Enable support for 16-bit segments" if EXPERT
1229	default y
1230	depends on MODIFY_LDT_SYSCALL
1231	help
1232	  This option is required by programs like Wine to run 16-bit
1233	  protected mode legacy code on x86 processors.  Disabling
1234	  this option saves about 300 bytes on i386, or around 6K text
1235	  plus 16K runtime memory on x86-64,
1236
1237config X86_ESPFIX32
1238	def_bool y
1239	depends on X86_16BIT && X86_32
1240
1241config X86_ESPFIX64
1242	def_bool y
1243	depends on X86_16BIT && X86_64
1244
1245config X86_VSYSCALL_EMULATION
1246	bool "Enable vsyscall emulation" if EXPERT
1247	default y
1248	depends on X86_64
1249	help
1250	  This enables emulation of the legacy vsyscall page.  Disabling
1251	  it is roughly equivalent to booting with vsyscall=none, except
1252	  that it will also disable the helpful warning if a program
1253	  tries to use a vsyscall.  With this option set to N, offending
1254	  programs will just segfault, citing addresses of the form
1255	  0xffffffffff600?00.
1256
1257	  This option is required by many programs built before 2013, and
1258	  care should be used even with newer programs if set to N.
1259
1260	  Disabling this option saves about 7K of kernel size and
1261	  possibly 4K of additional runtime pagetable memory.
1262
1263config X86_IOPL_IOPERM
1264	bool "IOPERM and IOPL Emulation"
1265	default y
1266	help
1267	  This enables the ioperm() and iopl() syscalls which are necessary
1268	  for legacy applications.
1269
1270	  Legacy IOPL support is an overbroad mechanism which allows user
1271	  space aside of accessing all 65536 I/O ports also to disable
1272	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1273	  capabilities and permission from potentially active security
1274	  modules.
1275
1276	  The emulation restricts the functionality of the syscall to
1277	  only allowing the full range I/O port access, but prevents the
1278	  ability to disable interrupts from user space which would be
1279	  granted if the hardware IOPL mechanism would be used.
1280
1281config TOSHIBA
1282	tristate "Toshiba Laptop support"
1283	depends on X86_32
1284	help
1285	  This adds a driver to safely access the System Management Mode of
1286	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1287	  not work on models with a Phoenix BIOS. The System Management Mode
1288	  is used to set the BIOS and power saving options on Toshiba portables.
1289
1290	  For information on utilities to make use of this driver see the
1291	  Toshiba Linux utilities web site at:
1292	  <http://www.buzzard.org.uk/toshiba/>.
1293
1294	  Say Y if you intend to run this kernel on a Toshiba portable.
1295	  Say N otherwise.
1296
1297config X86_REBOOTFIXUPS
1298	bool "Enable X86 board specific fixups for reboot"
1299	depends on X86_32
1300	help
1301	  This enables chipset and/or board specific fixups to be done
1302	  in order to get reboot to work correctly. This is only needed on
1303	  some combinations of hardware and BIOS. The symptom, for which
1304	  this config is intended, is when reboot ends with a stalled/hung
1305	  system.
1306
1307	  Currently, the only fixup is for the Geode machines using
1308	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1309
1310	  Say Y if you want to enable the fixup. Currently, it's safe to
1311	  enable this option even if you don't need it.
1312	  Say N otherwise.
1313
1314config MICROCODE
1315	def_bool y
1316	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1317	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1318
1319config MICROCODE_INITRD32
1320	def_bool y
1321	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1322
1323config MICROCODE_LATE_LOADING
1324	bool "Late microcode loading (DANGEROUS)"
1325	default n
1326	depends on MICROCODE && SMP
1327	help
1328	  Loading microcode late, when the system is up and executing instructions
1329	  is a tricky business and should be avoided if possible. Just the sequence
1330	  of synchronizing all cores and SMT threads is one fragile dance which does
1331	  not guarantee that cores might not softlock after the loading. Therefore,
1332	  use this at your own risk. Late loading taints the kernel unless the
1333	  microcode header indicates that it is safe for late loading via the
1334	  minimal revision check. This minimal revision check can be enforced on
1335	  the kernel command line with "microcode.minrev=Y".
1336
1337config MICROCODE_LATE_FORCE_MINREV
1338	bool "Enforce late microcode loading minimal revision check"
1339	default n
1340	depends on MICROCODE_LATE_LOADING
1341	help
1342	  To prevent that users load microcode late which modifies already
1343	  in use features, newer microcode patches have a minimum revision field
1344	  in the microcode header, which tells the kernel which minimum
1345	  revision must be active in the CPU to safely load that new microcode
1346	  late into the running system. If disabled the check will not
1347	  be enforced but the kernel will be tainted when the minimal
1348	  revision check fails.
1349
1350	  This minimal revision check can also be controlled via the
1351	  "microcode.minrev" parameter on the kernel command line.
1352
1353	  If unsure say Y.
1354
1355config X86_MSR
1356	tristate "/dev/cpu/*/msr - Model-specific register support"
1357	help
1358	  This device gives privileged processes access to the x86
1359	  Model-Specific Registers (MSRs).  It is a character device with
1360	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1361	  MSR accesses are directed to a specific CPU on multi-processor
1362	  systems.
1363
1364config X86_CPUID
1365	tristate "/dev/cpu/*/cpuid - CPU information support"
1366	help
1367	  This device gives processes access to the x86 CPUID instruction to
1368	  be executed on a specific processor.  It is a character device
1369	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1370	  /dev/cpu/31/cpuid.
1371
1372choice
1373	prompt "High Memory Support"
1374	default HIGHMEM4G
1375	depends on X86_32
1376
1377config NOHIGHMEM
1378	bool "off"
1379	help
1380	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1381	  However, the address space of 32-bit x86 processors is only 4
1382	  Gigabytes large. That means that, if you have a large amount of
1383	  physical memory, not all of it can be "permanently mapped" by the
1384	  kernel. The physical memory that's not permanently mapped is called
1385	  "high memory".
1386
1387	  If you are compiling a kernel which will never run on a machine with
1388	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1389	  choice and suitable for most users). This will result in a "3GB/1GB"
1390	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1391	  space and the remaining part of the 4GB virtual memory space is used
1392	  by the kernel to permanently map as much physical memory as
1393	  possible.
1394
1395	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1396	  answer "4GB" here.
1397
1398	  If more than 4 Gigabytes is used then answer "64GB" here. This
1399	  selection turns Intel PAE (Physical Address Extension) mode on.
1400	  PAE implements 3-level paging on IA32 processors. PAE is fully
1401	  supported by Linux, PAE mode is implemented on all recent Intel
1402	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1403	  then the kernel will not boot on CPUs that don't support PAE!
1404
1405	  The actual amount of total physical memory will either be
1406	  auto detected or can be forced by using a kernel command line option
1407	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1408	  your boot loader (lilo or loadlin) about how to pass options to the
1409	  kernel at boot time.)
1410
1411	  If unsure, say "off".
1412
1413config HIGHMEM4G
1414	bool "4GB"
1415	help
1416	  Select this if you have a 32-bit processor and between 1 and 4
1417	  gigabytes of physical RAM.
1418
1419config HIGHMEM64G
1420	bool "64GB"
1421	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1422	select X86_PAE
1423	help
1424	  Select this if you have a 32-bit processor and more than 4
1425	  gigabytes of physical RAM.
1426
1427endchoice
1428
1429choice
1430	prompt "Memory split" if EXPERT
1431	default VMSPLIT_3G
1432	depends on X86_32
1433	help
1434	  Select the desired split between kernel and user memory.
1435
1436	  If the address range available to the kernel is less than the
1437	  physical memory installed, the remaining memory will be available
1438	  as "high memory". Accessing high memory is a little more costly
1439	  than low memory, as it needs to be mapped into the kernel first.
1440	  Note that increasing the kernel address space limits the range
1441	  available to user programs, making the address space there
1442	  tighter.  Selecting anything other than the default 3G/1G split
1443	  will also likely make your kernel incompatible with binary-only
1444	  kernel modules.
1445
1446	  If you are not absolutely sure what you are doing, leave this
1447	  option alone!
1448
1449	config VMSPLIT_3G
1450		bool "3G/1G user/kernel split"
1451	config VMSPLIT_3G_OPT
1452		depends on !X86_PAE
1453		bool "3G/1G user/kernel split (for full 1G low memory)"
1454	config VMSPLIT_2G
1455		bool "2G/2G user/kernel split"
1456	config VMSPLIT_2G_OPT
1457		depends on !X86_PAE
1458		bool "2G/2G user/kernel split (for full 2G low memory)"
1459	config VMSPLIT_1G
1460		bool "1G/3G user/kernel split"
1461endchoice
1462
1463config PAGE_OFFSET
1464	hex
1465	default 0xB0000000 if VMSPLIT_3G_OPT
1466	default 0x80000000 if VMSPLIT_2G
1467	default 0x78000000 if VMSPLIT_2G_OPT
1468	default 0x40000000 if VMSPLIT_1G
1469	default 0xC0000000
1470	depends on X86_32
1471
1472config HIGHMEM
1473	def_bool y
1474	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1475
1476config X86_PAE
1477	bool "PAE (Physical Address Extension) Support"
1478	depends on X86_32 && !HIGHMEM4G
1479	select PHYS_ADDR_T_64BIT
1480	select SWIOTLB
1481	help
1482	  PAE is required for NX support, and furthermore enables
1483	  larger swapspace support for non-overcommit purposes. It
1484	  has the cost of more pagetable lookup overhead, and also
1485	  consumes more pagetable space per process.
1486
1487config X86_5LEVEL
1488	bool "Enable 5-level page tables support"
1489	default y
1490	select DYNAMIC_MEMORY_LAYOUT
1491	select SPARSEMEM_VMEMMAP
1492	depends on X86_64
1493	help
1494	  5-level paging enables access to larger address space:
1495	  up to 128 PiB of virtual address space and 4 PiB of
1496	  physical address space.
1497
1498	  It will be supported by future Intel CPUs.
1499
1500	  A kernel with the option enabled can be booted on machines that
1501	  support 4- or 5-level paging.
1502
1503	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1504	  information.
1505
1506	  Say N if unsure.
1507
1508config X86_DIRECT_GBPAGES
1509	def_bool y
1510	depends on X86_64
1511	help
1512	  Certain kernel features effectively disable kernel
1513	  linear 1 GB mappings (even if the CPU otherwise
1514	  supports them), so don't confuse the user by printing
1515	  that we have them enabled.
1516
1517config X86_CPA_STATISTICS
1518	bool "Enable statistic for Change Page Attribute"
1519	depends on DEBUG_FS
1520	help
1521	  Expose statistics about the Change Page Attribute mechanism, which
1522	  helps to determine the effectiveness of preserving large and huge
1523	  page mappings when mapping protections are changed.
1524
1525config X86_MEM_ENCRYPT
1526	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1527	select DYNAMIC_PHYSICAL_MASK
1528	def_bool n
1529
1530config AMD_MEM_ENCRYPT
1531	bool "AMD Secure Memory Encryption (SME) support"
1532	depends on X86_64 && CPU_SUP_AMD
1533	depends on EFI_STUB
1534	select DMA_COHERENT_POOL
1535	select ARCH_USE_MEMREMAP_PROT
1536	select INSTRUCTION_DECODER
1537	select ARCH_HAS_CC_PLATFORM
1538	select X86_MEM_ENCRYPT
1539	select UNACCEPTED_MEMORY
1540	help
1541	  Say yes to enable support for the encryption of system memory.
1542	  This requires an AMD processor that supports Secure Memory
1543	  Encryption (SME).
1544
1545# Common NUMA Features
1546config NUMA
1547	bool "NUMA Memory Allocation and Scheduler Support"
1548	depends on SMP
1549	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1550	default y if X86_BIGSMP
1551	select USE_PERCPU_NUMA_NODE_ID
1552	help
1553	  Enable NUMA (Non-Uniform Memory Access) support.
1554
1555	  The kernel will try to allocate memory used by a CPU on the
1556	  local memory controller of the CPU and add some more
1557	  NUMA awareness to the kernel.
1558
1559	  For 64-bit this is recommended if the system is Intel Core i7
1560	  (or later), AMD Opteron, or EM64T NUMA.
1561
1562	  For 32-bit this is only needed if you boot a 32-bit
1563	  kernel on a 64-bit NUMA platform.
1564
1565	  Otherwise, you should say N.
1566
1567config AMD_NUMA
1568	def_bool y
1569	prompt "Old style AMD Opteron NUMA detection"
1570	depends on X86_64 && NUMA && PCI
1571	help
1572	  Enable AMD NUMA node topology detection.  You should say Y here if
1573	  you have a multi processor AMD system. This uses an old method to
1574	  read the NUMA configuration directly from the builtin Northbridge
1575	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1576	  which also takes priority if both are compiled in.
1577
1578config X86_64_ACPI_NUMA
1579	def_bool y
1580	prompt "ACPI NUMA detection"
1581	depends on X86_64 && NUMA && ACPI && PCI
1582	select ACPI_NUMA
1583	help
1584	  Enable ACPI SRAT based node topology detection.
1585
1586config NUMA_EMU
1587	bool "NUMA emulation"
1588	depends on NUMA
1589	help
1590	  Enable NUMA emulation. A flat machine will be split
1591	  into virtual nodes when booted with "numa=fake=N", where N is the
1592	  number of nodes. This is only useful for debugging.
1593
1594config NODES_SHIFT
1595	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1596	range 1 10
1597	default "10" if MAXSMP
1598	default "6" if X86_64
1599	default "3"
1600	depends on NUMA
1601	help
1602	  Specify the maximum number of NUMA Nodes available on the target
1603	  system.  Increases memory reserved to accommodate various tables.
1604
1605config ARCH_FLATMEM_ENABLE
1606	def_bool y
1607	depends on X86_32 && !NUMA
1608
1609config ARCH_SPARSEMEM_ENABLE
1610	def_bool y
1611	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1612	select SPARSEMEM_STATIC if X86_32
1613	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1614
1615config ARCH_SPARSEMEM_DEFAULT
1616	def_bool X86_64 || (NUMA && X86_32)
1617
1618config ARCH_SELECT_MEMORY_MODEL
1619	def_bool y
1620	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1621
1622config ARCH_MEMORY_PROBE
1623	bool "Enable sysfs memory/probe interface"
1624	depends on MEMORY_HOTPLUG
1625	help
1626	  This option enables a sysfs memory/probe interface for testing.
1627	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1628	  If you are unsure how to answer this question, answer N.
1629
1630config ARCH_PROC_KCORE_TEXT
1631	def_bool y
1632	depends on X86_64 && PROC_KCORE
1633
1634config ILLEGAL_POINTER_VALUE
1635	hex
1636	default 0 if X86_32
1637	default 0xdead000000000000 if X86_64
1638
1639config X86_PMEM_LEGACY_DEVICE
1640	bool
1641
1642config X86_PMEM_LEGACY
1643	tristate "Support non-standard NVDIMMs and ADR protected memory"
1644	depends on PHYS_ADDR_T_64BIT
1645	depends on BLK_DEV
1646	select X86_PMEM_LEGACY_DEVICE
1647	select NUMA_KEEP_MEMINFO if NUMA
1648	select LIBNVDIMM
1649	help
1650	  Treat memory marked using the non-standard e820 type of 12 as used
1651	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1652	  The kernel will offer these regions to the 'pmem' driver so
1653	  they can be used for persistent storage.
1654
1655	  Say Y if unsure.
1656
1657config HIGHPTE
1658	bool "Allocate 3rd-level pagetables from highmem"
1659	depends on HIGHMEM
1660	help
1661	  The VM uses one page table entry for each page of physical memory.
1662	  For systems with a lot of RAM, this can be wasteful of precious
1663	  low memory.  Setting this option will put user-space page table
1664	  entries in high memory.
1665
1666config X86_CHECK_BIOS_CORRUPTION
1667	bool "Check for low memory corruption"
1668	help
1669	  Periodically check for memory corruption in low memory, which
1670	  is suspected to be caused by BIOS.  Even when enabled in the
1671	  configuration, it is disabled at runtime.  Enable it by
1672	  setting "memory_corruption_check=1" on the kernel command
1673	  line.  By default it scans the low 64k of memory every 60
1674	  seconds; see the memory_corruption_check_size and
1675	  memory_corruption_check_period parameters in
1676	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1677
1678	  When enabled with the default parameters, this option has
1679	  almost no overhead, as it reserves a relatively small amount
1680	  of memory and scans it infrequently.  It both detects corruption
1681	  and prevents it from affecting the running system.
1682
1683	  It is, however, intended as a diagnostic tool; if repeatable
1684	  BIOS-originated corruption always affects the same memory,
1685	  you can use memmap= to prevent the kernel from using that
1686	  memory.
1687
1688config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1689	bool "Set the default setting of memory_corruption_check"
1690	depends on X86_CHECK_BIOS_CORRUPTION
1691	default y
1692	help
1693	  Set whether the default state of memory_corruption_check is
1694	  on or off.
1695
1696config MATH_EMULATION
1697	bool
1698	depends on MODIFY_LDT_SYSCALL
1699	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1700	help
1701	  Linux can emulate a math coprocessor (used for floating point
1702	  operations) if you don't have one. 486DX and Pentium processors have
1703	  a math coprocessor built in, 486SX and 386 do not, unless you added
1704	  a 487DX or 387, respectively. (The messages during boot time can
1705	  give you some hints here ["man dmesg"].) Everyone needs either a
1706	  coprocessor or this emulation.
1707
1708	  If you don't have a math coprocessor, you need to say Y here; if you
1709	  say Y here even though you have a coprocessor, the coprocessor will
1710	  be used nevertheless. (This behavior can be changed with the kernel
1711	  command line option "no387", which comes handy if your coprocessor
1712	  is broken. Try "man bootparam" or see the documentation of your boot
1713	  loader (lilo or loadlin) about how to pass options to the kernel at
1714	  boot time.) This means that it is a good idea to say Y here if you
1715	  intend to use this kernel on different machines.
1716
1717	  More information about the internals of the Linux math coprocessor
1718	  emulation can be found in <file:arch/x86/math-emu/README>.
1719
1720	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1721	  kernel, it won't hurt.
1722
1723config MTRR
1724	def_bool y
1725	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1726	help
1727	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1728	  the Memory Type Range Registers (MTRRs) may be used to control
1729	  processor access to memory ranges. This is most useful if you have
1730	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1731	  allows bus write transfers to be combined into a larger transfer
1732	  before bursting over the PCI/AGP bus. This can increase performance
1733	  of image write operations 2.5 times or more. Saying Y here creates a
1734	  /proc/mtrr file which may be used to manipulate your processor's
1735	  MTRRs. Typically the X server should use this.
1736
1737	  This code has a reasonably generic interface so that similar
1738	  control registers on other processors can be easily supported
1739	  as well:
1740
1741	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1742	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1743	  these, the ARRs are used to emulate the MTRRs.
1744	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1745	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1746	  write-combining. All of these processors are supported by this code
1747	  and it makes sense to say Y here if you have one of them.
1748
1749	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1750	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1751	  can lead to all sorts of problems, so it's good to say Y here.
1752
1753	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1754	  just add about 9 KB to your kernel.
1755
1756	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1757
1758config MTRR_SANITIZER
1759	def_bool y
1760	prompt "MTRR cleanup support"
1761	depends on MTRR
1762	help
1763	  Convert MTRR layout from continuous to discrete, so X drivers can
1764	  add writeback entries.
1765
1766	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1767	  The largest mtrr entry size for a continuous block can be set with
1768	  mtrr_chunk_size.
1769
1770	  If unsure, say Y.
1771
1772config MTRR_SANITIZER_ENABLE_DEFAULT
1773	int "MTRR cleanup enable value (0-1)"
1774	range 0 1
1775	default "0"
1776	depends on MTRR_SANITIZER
1777	help
1778	  Enable mtrr cleanup default value
1779
1780config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1781	int "MTRR cleanup spare reg num (0-7)"
1782	range 0 7
1783	default "1"
1784	depends on MTRR_SANITIZER
1785	help
1786	  mtrr cleanup spare entries default, it can be changed via
1787	  mtrr_spare_reg_nr=N on the kernel command line.
1788
1789config X86_PAT
1790	def_bool y
1791	prompt "x86 PAT support" if EXPERT
1792	depends on MTRR
1793	help
1794	  Use PAT attributes to setup page level cache control.
1795
1796	  PATs are the modern equivalents of MTRRs and are much more
1797	  flexible than MTRRs.
1798
1799	  Say N here if you see bootup problems (boot crash, boot hang,
1800	  spontaneous reboots) or a non-working video driver.
1801
1802	  If unsure, say Y.
1803
1804config ARCH_USES_PG_UNCACHED
1805	def_bool y
1806	depends on X86_PAT
1807
1808config X86_UMIP
1809	def_bool y
1810	prompt "User Mode Instruction Prevention" if EXPERT
1811	help
1812	  User Mode Instruction Prevention (UMIP) is a security feature in
1813	  some x86 processors. If enabled, a general protection fault is
1814	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1815	  executed in user mode. These instructions unnecessarily expose
1816	  information about the hardware state.
1817
1818	  The vast majority of applications do not use these instructions.
1819	  For the very few that do, software emulation is provided in
1820	  specific cases in protected and virtual-8086 modes. Emulated
1821	  results are dummy.
1822
1823config CC_HAS_IBT
1824	# GCC >= 9 and binutils >= 2.29
1825	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1826	# Clang/LLVM >= 14
1827	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1828	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1829	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1830		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1831		  $(as-instr,endbr64)
1832
1833config X86_CET
1834	def_bool n
1835	help
1836	  CET features configured (Shadow stack or IBT)
1837
1838config X86_KERNEL_IBT
1839	prompt "Indirect Branch Tracking"
1840	def_bool y
1841	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1842	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1843	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1844	select OBJTOOL
1845	select X86_CET
1846	help
1847	  Build the kernel with support for Indirect Branch Tracking, a
1848	  hardware support course-grain forward-edge Control Flow Integrity
1849	  protection. It enforces that all indirect calls must land on
1850	  an ENDBR instruction, as such, the compiler will instrument the
1851	  code with them to make this happen.
1852
1853	  In addition to building the kernel with IBT, seal all functions that
1854	  are not indirect call targets, avoiding them ever becoming one.
1855
1856	  This requires LTO like objtool runs and will slow down the build. It
1857	  does significantly reduce the number of ENDBR instructions in the
1858	  kernel image.
1859
1860config X86_INTEL_MEMORY_PROTECTION_KEYS
1861	prompt "Memory Protection Keys"
1862	def_bool y
1863	# Note: only available in 64-bit mode
1864	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1865	select ARCH_USES_HIGH_VMA_FLAGS
1866	select ARCH_HAS_PKEYS
1867	help
1868	  Memory Protection Keys provides a mechanism for enforcing
1869	  page-based protections, but without requiring modification of the
1870	  page tables when an application changes protection domains.
1871
1872	  For details, see Documentation/core-api/protection-keys.rst
1873
1874	  If unsure, say y.
1875
1876choice
1877	prompt "TSX enable mode"
1878	depends on CPU_SUP_INTEL
1879	default X86_INTEL_TSX_MODE_OFF
1880	help
1881	  Intel's TSX (Transactional Synchronization Extensions) feature
1882	  allows to optimize locking protocols through lock elision which
1883	  can lead to a noticeable performance boost.
1884
1885	  On the other hand it has been shown that TSX can be exploited
1886	  to form side channel attacks (e.g. TAA) and chances are there
1887	  will be more of those attacks discovered in the future.
1888
1889	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1890	  might override this decision by tsx=on the command line parameter.
1891	  Even with TSX enabled, the kernel will attempt to enable the best
1892	  possible TAA mitigation setting depending on the microcode available
1893	  for the particular machine.
1894
1895	  This option allows to set the default tsx mode between tsx=on, =off
1896	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1897	  details.
1898
1899	  Say off if not sure, auto if TSX is in use but it should be used on safe
1900	  platforms or on if TSX is in use and the security aspect of tsx is not
1901	  relevant.
1902
1903config X86_INTEL_TSX_MODE_OFF
1904	bool "off"
1905	help
1906	  TSX is disabled if possible - equals to tsx=off command line parameter.
1907
1908config X86_INTEL_TSX_MODE_ON
1909	bool "on"
1910	help
1911	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1912	  line parameter.
1913
1914config X86_INTEL_TSX_MODE_AUTO
1915	bool "auto"
1916	help
1917	  TSX is enabled on TSX capable HW that is believed to be safe against
1918	  side channel attacks- equals the tsx=auto command line parameter.
1919endchoice
1920
1921config X86_SGX
1922	bool "Software Guard eXtensions (SGX)"
1923	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1924	depends on CRYPTO=y
1925	depends on CRYPTO_SHA256=y
1926	select MMU_NOTIFIER
1927	select NUMA_KEEP_MEMINFO if NUMA
1928	select XARRAY_MULTI
1929	help
1930	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1931	  that can be used by applications to set aside private regions of code
1932	  and data, referred to as enclaves. An enclave's private memory can
1933	  only be accessed by code running within the enclave. Accesses from
1934	  outside the enclave, including other enclaves, are disallowed by
1935	  hardware.
1936
1937	  If unsure, say N.
1938
1939config X86_USER_SHADOW_STACK
1940	bool "X86 userspace shadow stack"
1941	depends on AS_WRUSS
1942	depends on X86_64
1943	select ARCH_USES_HIGH_VMA_FLAGS
1944	select X86_CET
1945	help
1946	  Shadow stack protection is a hardware feature that detects function
1947	  return address corruption.  This helps mitigate ROP attacks.
1948	  Applications must be enabled to use it, and old userspace does not
1949	  get protection "for free".
1950
1951	  CPUs supporting shadow stacks were first released in 2020.
1952
1953	  See Documentation/arch/x86/shstk.rst for more information.
1954
1955	  If unsure, say N.
1956
1957config EFI
1958	bool "EFI runtime service support"
1959	depends on ACPI
1960	select UCS2_STRING
1961	select EFI_RUNTIME_WRAPPERS
1962	select ARCH_USE_MEMREMAP_PROT
1963	select EFI_RUNTIME_MAP if KEXEC_CORE
1964	help
1965	  This enables the kernel to use EFI runtime services that are
1966	  available (such as the EFI variable services).
1967
1968	  This option is only useful on systems that have EFI firmware.
1969	  In addition, you should use the latest ELILO loader available
1970	  at <http://elilo.sourceforge.net> in order to take advantage
1971	  of EFI runtime services. However, even with this option, the
1972	  resultant kernel should continue to boot on existing non-EFI
1973	  platforms.
1974
1975config EFI_STUB
1976	bool "EFI stub support"
1977	depends on EFI
1978	select RELOCATABLE
1979	help
1980	  This kernel feature allows a bzImage to be loaded directly
1981	  by EFI firmware without the use of a bootloader.
1982
1983	  See Documentation/admin-guide/efi-stub.rst for more information.
1984
1985config EFI_HANDOVER_PROTOCOL
1986	bool "EFI handover protocol (DEPRECATED)"
1987	depends on EFI_STUB
1988	default y
1989	help
1990	  Select this in order to include support for the deprecated EFI
1991	  handover protocol, which defines alternative entry points into the
1992	  EFI stub.  This is a practice that has no basis in the UEFI
1993	  specification, and requires a priori knowledge on the part of the
1994	  bootloader about Linux/x86 specific ways of passing the command line
1995	  and initrd, and where in memory those assets may be loaded.
1996
1997	  If in doubt, say Y. Even though the corresponding support is not
1998	  present in upstream GRUB or other bootloaders, most distros build
1999	  GRUB with numerous downstream patches applied, and may rely on the
2000	  handover protocol as as result.
2001
2002config EFI_MIXED
2003	bool "EFI mixed-mode support"
2004	depends on EFI_STUB && X86_64
2005	help
2006	  Enabling this feature allows a 64-bit kernel to be booted
2007	  on a 32-bit firmware, provided that your CPU supports 64-bit
2008	  mode.
2009
2010	  Note that it is not possible to boot a mixed-mode enabled
2011	  kernel via the EFI boot stub - a bootloader that supports
2012	  the EFI handover protocol must be used.
2013
2014	  If unsure, say N.
2015
2016config EFI_FAKE_MEMMAP
2017	bool "Enable EFI fake memory map"
2018	depends on EFI
2019	help
2020	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
2021	  this parameter, you can add arbitrary attribute to specific memory
2022	  range by updating original (firmware provided) EFI memmap.  This is
2023	  useful for debugging of EFI memmap related feature, e.g., Address
2024	  Range Mirroring feature.
2025
2026config EFI_MAX_FAKE_MEM
2027	int "maximum allowable number of ranges in efi_fake_mem boot option"
2028	depends on EFI_FAKE_MEMMAP
2029	range 1 128
2030	default 8
2031	help
2032	  Maximum allowable number of ranges in efi_fake_mem boot option.
2033	  Ranges can be set up to this value using comma-separated list.
2034	  The default value is 8.
2035
2036config EFI_RUNTIME_MAP
2037	bool "Export EFI runtime maps to sysfs" if EXPERT
2038	depends on EFI
2039	help
2040	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2041	  That memory map is required by the 2nd kernel to set up EFI virtual
2042	  mappings after kexec, but can also be used for debugging purposes.
2043
2044	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2045
2046source "kernel/Kconfig.hz"
2047
2048config ARCH_SUPPORTS_KEXEC
2049	def_bool y
2050
2051config ARCH_SUPPORTS_KEXEC_FILE
2052	def_bool X86_64
2053
2054config ARCH_SELECTS_KEXEC_FILE
2055	def_bool y
2056	depends on KEXEC_FILE
2057	select HAVE_IMA_KEXEC if IMA
2058
2059config ARCH_SUPPORTS_KEXEC_PURGATORY
2060	def_bool y
2061
2062config ARCH_SUPPORTS_KEXEC_SIG
2063	def_bool y
2064
2065config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2066	def_bool y
2067
2068config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2069	def_bool y
2070
2071config ARCH_SUPPORTS_KEXEC_JUMP
2072	def_bool y
2073
2074config ARCH_SUPPORTS_CRASH_DUMP
2075	def_bool X86_64 || (X86_32 && HIGHMEM)
2076
2077config ARCH_SUPPORTS_CRASH_HOTPLUG
2078	def_bool y
2079
2080config PHYSICAL_START
2081	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2082	default "0x1000000"
2083	help
2084	  This gives the physical address where the kernel is loaded.
2085
2086	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2087	  bzImage will decompress itself to above physical address and
2088	  run from there. Otherwise, bzImage will run from the address where
2089	  it has been loaded by the boot loader and will ignore above physical
2090	  address.
2091
2092	  In normal kdump cases one does not have to set/change this option
2093	  as now bzImage can be compiled as a completely relocatable image
2094	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2095	  address. This option is mainly useful for the folks who don't want
2096	  to use a bzImage for capturing the crash dump and want to use a
2097	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2098	  to be specifically compiled to run from a specific memory area
2099	  (normally a reserved region) and this option comes handy.
2100
2101	  So if you are using bzImage for capturing the crash dump,
2102	  leave the value here unchanged to 0x1000000 and set
2103	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2104	  for capturing the crash dump change this value to start of
2105	  the reserved region.  In other words, it can be set based on
2106	  the "X" value as specified in the "crashkernel=YM@XM"
2107	  command line boot parameter passed to the panic-ed
2108	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2109	  for more details about crash dumps.
2110
2111	  Usage of bzImage for capturing the crash dump is recommended as
2112	  one does not have to build two kernels. Same kernel can be used
2113	  as production kernel and capture kernel. Above option should have
2114	  gone away after relocatable bzImage support is introduced. But it
2115	  is present because there are users out there who continue to use
2116	  vmlinux for dump capture. This option should go away down the
2117	  line.
2118
2119	  Don't change this unless you know what you are doing.
2120
2121config RELOCATABLE
2122	bool "Build a relocatable kernel"
2123	default y
2124	help
2125	  This builds a kernel image that retains relocation information
2126	  so it can be loaded someplace besides the default 1MB.
2127	  The relocations tend to make the kernel binary about 10% larger,
2128	  but are discarded at runtime.
2129
2130	  One use is for the kexec on panic case where the recovery kernel
2131	  must live at a different physical address than the primary
2132	  kernel.
2133
2134	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2135	  it has been loaded at and the compile time physical address
2136	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2137
2138config RANDOMIZE_BASE
2139	bool "Randomize the address of the kernel image (KASLR)"
2140	depends on RELOCATABLE
2141	default y
2142	help
2143	  In support of Kernel Address Space Layout Randomization (KASLR),
2144	  this randomizes the physical address at which the kernel image
2145	  is decompressed and the virtual address where the kernel
2146	  image is mapped, as a security feature that deters exploit
2147	  attempts relying on knowledge of the location of kernel
2148	  code internals.
2149
2150	  On 64-bit, the kernel physical and virtual addresses are
2151	  randomized separately. The physical address will be anywhere
2152	  between 16MB and the top of physical memory (up to 64TB). The
2153	  virtual address will be randomized from 16MB up to 1GB (9 bits
2154	  of entropy). Note that this also reduces the memory space
2155	  available to kernel modules from 1.5GB to 1GB.
2156
2157	  On 32-bit, the kernel physical and virtual addresses are
2158	  randomized together. They will be randomized from 16MB up to
2159	  512MB (8 bits of entropy).
2160
2161	  Entropy is generated using the RDRAND instruction if it is
2162	  supported. If RDTSC is supported, its value is mixed into
2163	  the entropy pool as well. If neither RDRAND nor RDTSC are
2164	  supported, then entropy is read from the i8254 timer. The
2165	  usable entropy is limited by the kernel being built using
2166	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2167	  minimum of 2MB. As a result, only 10 bits of entropy are
2168	  theoretically possible, but the implementations are further
2169	  limited due to memory layouts.
2170
2171	  If unsure, say Y.
2172
2173# Relocation on x86 needs some additional build support
2174config X86_NEED_RELOCS
2175	def_bool y
2176	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2177
2178config PHYSICAL_ALIGN
2179	hex "Alignment value to which kernel should be aligned"
2180	default "0x200000"
2181	range 0x2000 0x1000000 if X86_32
2182	range 0x200000 0x1000000 if X86_64
2183	help
2184	  This value puts the alignment restrictions on physical address
2185	  where kernel is loaded and run from. Kernel is compiled for an
2186	  address which meets above alignment restriction.
2187
2188	  If bootloader loads the kernel at a non-aligned address and
2189	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2190	  address aligned to above value and run from there.
2191
2192	  If bootloader loads the kernel at a non-aligned address and
2193	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2194	  load address and decompress itself to the address it has been
2195	  compiled for and run from there. The address for which kernel is
2196	  compiled already meets above alignment restrictions. Hence the
2197	  end result is that kernel runs from a physical address meeting
2198	  above alignment restrictions.
2199
2200	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2201	  this value must be a multiple of 0x200000.
2202
2203	  Don't change this unless you know what you are doing.
2204
2205config DYNAMIC_MEMORY_LAYOUT
2206	bool
2207	help
2208	  This option makes base addresses of vmalloc and vmemmap as well as
2209	  __PAGE_OFFSET movable during boot.
2210
2211config RANDOMIZE_MEMORY
2212	bool "Randomize the kernel memory sections"
2213	depends on X86_64
2214	depends on RANDOMIZE_BASE
2215	select DYNAMIC_MEMORY_LAYOUT
2216	default RANDOMIZE_BASE
2217	help
2218	  Randomizes the base virtual address of kernel memory sections
2219	  (physical memory mapping, vmalloc & vmemmap). This security feature
2220	  makes exploits relying on predictable memory locations less reliable.
2221
2222	  The order of allocations remains unchanged. Entropy is generated in
2223	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2224	  configuration have in average 30,000 different possible virtual
2225	  addresses for each memory section.
2226
2227	  If unsure, say Y.
2228
2229config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2230	hex "Physical memory mapping padding" if EXPERT
2231	depends on RANDOMIZE_MEMORY
2232	default "0xa" if MEMORY_HOTPLUG
2233	default "0x0"
2234	range 0x1 0x40 if MEMORY_HOTPLUG
2235	range 0x0 0x40
2236	help
2237	  Define the padding in terabytes added to the existing physical
2238	  memory size during kernel memory randomization. It is useful
2239	  for memory hotplug support but reduces the entropy available for
2240	  address randomization.
2241
2242	  If unsure, leave at the default value.
2243
2244config ADDRESS_MASKING
2245	bool "Linear Address Masking support"
2246	depends on X86_64
2247	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2248	help
2249	  Linear Address Masking (LAM) modifies the checking that is applied
2250	  to 64-bit linear addresses, allowing software to use of the
2251	  untranslated address bits for metadata.
2252
2253	  The capability can be used for efficient address sanitizers (ASAN)
2254	  implementation and for optimizations in JITs.
2255
2256config HOTPLUG_CPU
2257	def_bool y
2258	depends on SMP
2259
2260config COMPAT_VDSO
2261	def_bool n
2262	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2263	depends on COMPAT_32
2264	help
2265	  Certain buggy versions of glibc will crash if they are
2266	  presented with a 32-bit vDSO that is not mapped at the address
2267	  indicated in its segment table.
2268
2269	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2270	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2271	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2272	  the only released version with the bug, but OpenSUSE 9
2273	  contains a buggy "glibc 2.3.2".
2274
2275	  The symptom of the bug is that everything crashes on startup, saying:
2276	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2277
2278	  Saying Y here changes the default value of the vdso32 boot
2279	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2280	  This works around the glibc bug but hurts performance.
2281
2282	  If unsure, say N: if you are compiling your own kernel, you
2283	  are unlikely to be using a buggy version of glibc.
2284
2285choice
2286	prompt "vsyscall table for legacy applications"
2287	depends on X86_64
2288	default LEGACY_VSYSCALL_XONLY
2289	help
2290	  Legacy user code that does not know how to find the vDSO expects
2291	  to be able to issue three syscalls by calling fixed addresses in
2292	  kernel space. Since this location is not randomized with ASLR,
2293	  it can be used to assist security vulnerability exploitation.
2294
2295	  This setting can be changed at boot time via the kernel command
2296	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2297	  is deprecated and can only be enabled using the kernel command
2298	  line.
2299
2300	  On a system with recent enough glibc (2.14 or newer) and no
2301	  static binaries, you can say None without a performance penalty
2302	  to improve security.
2303
2304	  If unsure, select "Emulate execution only".
2305
2306	config LEGACY_VSYSCALL_XONLY
2307		bool "Emulate execution only"
2308		help
2309		  The kernel traps and emulates calls into the fixed vsyscall
2310		  address mapping and does not allow reads.  This
2311		  configuration is recommended when userspace might use the
2312		  legacy vsyscall area but support for legacy binary
2313		  instrumentation of legacy code is not needed.  It mitigates
2314		  certain uses of the vsyscall area as an ASLR-bypassing
2315		  buffer.
2316
2317	config LEGACY_VSYSCALL_NONE
2318		bool "None"
2319		help
2320		  There will be no vsyscall mapping at all. This will
2321		  eliminate any risk of ASLR bypass due to the vsyscall
2322		  fixed address mapping. Attempts to use the vsyscalls
2323		  will be reported to dmesg, so that either old or
2324		  malicious userspace programs can be identified.
2325
2326endchoice
2327
2328config CMDLINE_BOOL
2329	bool "Built-in kernel command line"
2330	help
2331	  Allow for specifying boot arguments to the kernel at
2332	  build time.  On some systems (e.g. embedded ones), it is
2333	  necessary or convenient to provide some or all of the
2334	  kernel boot arguments with the kernel itself (that is,
2335	  to not rely on the boot loader to provide them.)
2336
2337	  To compile command line arguments into the kernel,
2338	  set this option to 'Y', then fill in the
2339	  boot arguments in CONFIG_CMDLINE.
2340
2341	  Systems with fully functional boot loaders (i.e. non-embedded)
2342	  should leave this option set to 'N'.
2343
2344config CMDLINE
2345	string "Built-in kernel command string"
2346	depends on CMDLINE_BOOL
2347	default ""
2348	help
2349	  Enter arguments here that should be compiled into the kernel
2350	  image and used at boot time.  If the boot loader provides a
2351	  command line at boot time, it is appended to this string to
2352	  form the full kernel command line, when the system boots.
2353
2354	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2355	  change this behavior.
2356
2357	  In most cases, the command line (whether built-in or provided
2358	  by the boot loader) should specify the device for the root
2359	  file system.
2360
2361config CMDLINE_OVERRIDE
2362	bool "Built-in command line overrides boot loader arguments"
2363	depends on CMDLINE_BOOL && CMDLINE != ""
2364	help
2365	  Set this option to 'Y' to have the kernel ignore the boot loader
2366	  command line, and use ONLY the built-in command line.
2367
2368	  This is used to work around broken boot loaders.  This should
2369	  be set to 'N' under normal conditions.
2370
2371config MODIFY_LDT_SYSCALL
2372	bool "Enable the LDT (local descriptor table)" if EXPERT
2373	default y
2374	help
2375	  Linux can allow user programs to install a per-process x86
2376	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2377	  call.  This is required to run 16-bit or segmented code such as
2378	  DOSEMU or some Wine programs.  It is also used by some very old
2379	  threading libraries.
2380
2381	  Enabling this feature adds a small amount of overhead to
2382	  context switches and increases the low-level kernel attack
2383	  surface.  Disabling it removes the modify_ldt(2) system call.
2384
2385	  Saying 'N' here may make sense for embedded or server kernels.
2386
2387config STRICT_SIGALTSTACK_SIZE
2388	bool "Enforce strict size checking for sigaltstack"
2389	depends on DYNAMIC_SIGFRAME
2390	help
2391	  For historical reasons MINSIGSTKSZ is a constant which became
2392	  already too small with AVX512 support. Add a mechanism to
2393	  enforce strict checking of the sigaltstack size against the
2394	  real size of the FPU frame. This option enables the check
2395	  by default. It can also be controlled via the kernel command
2396	  line option 'strict_sas_size' independent of this config
2397	  switch. Enabling it might break existing applications which
2398	  allocate a too small sigaltstack but 'work' because they
2399	  never get a signal delivered.
2400
2401	  Say 'N' unless you want to really enforce this check.
2402
2403source "kernel/livepatch/Kconfig"
2404
2405endmenu
2406
2407config CC_HAS_SLS
2408	def_bool $(cc-option,-mharden-sls=all)
2409
2410config CC_HAS_RETURN_THUNK
2411	def_bool $(cc-option,-mfunction-return=thunk-extern)
2412
2413config CC_HAS_ENTRY_PADDING
2414	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2415
2416config FUNCTION_PADDING_CFI
2417	int
2418	default 59 if FUNCTION_ALIGNMENT_64B
2419	default 27 if FUNCTION_ALIGNMENT_32B
2420	default 11 if FUNCTION_ALIGNMENT_16B
2421	default  3 if FUNCTION_ALIGNMENT_8B
2422	default  0
2423
2424# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2425# except Kconfig can't do arithmetic :/
2426config FUNCTION_PADDING_BYTES
2427	int
2428	default FUNCTION_PADDING_CFI if CFI_CLANG
2429	default FUNCTION_ALIGNMENT
2430
2431config CALL_PADDING
2432	def_bool n
2433	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2434	select FUNCTION_ALIGNMENT_16B
2435
2436config FINEIBT
2437	def_bool y
2438	depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE
2439	select CALL_PADDING
2440
2441config HAVE_CALL_THUNKS
2442	def_bool y
2443	depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
2444
2445config CALL_THUNKS
2446	def_bool n
2447	select CALL_PADDING
2448
2449config PREFIX_SYMBOLS
2450	def_bool y
2451	depends on CALL_PADDING && !CFI_CLANG
2452
2453menuconfig CPU_MITIGATIONS
2454	bool "Mitigations for CPU vulnerabilities"
2455	default y
2456	help
2457	  Say Y here to enable options which enable mitigations for hardware
2458	  vulnerabilities (usually related to speculative execution).
2459	  Mitigations can be disabled or restricted to SMT systems at runtime
2460	  via the "mitigations" kernel parameter.
2461
2462	  If you say N, all mitigations will be disabled.  This CANNOT be
2463	  overridden at runtime.
2464
2465	  Say 'Y', unless you really know what you are doing.
2466
2467if CPU_MITIGATIONS
2468
2469config PAGE_TABLE_ISOLATION
2470	bool "Remove the kernel mapping in user mode"
2471	default y
2472	depends on (X86_64 || X86_PAE)
2473	help
2474	  This feature reduces the number of hardware side channels by
2475	  ensuring that the majority of kernel addresses are not mapped
2476	  into userspace.
2477
2478	  See Documentation/arch/x86/pti.rst for more details.
2479
2480config RETPOLINE
2481	bool "Avoid speculative indirect branches in kernel"
2482	select OBJTOOL if HAVE_OBJTOOL
2483	default y
2484	help
2485	  Compile kernel with the retpoline compiler options to guard against
2486	  kernel-to-user data leaks by avoiding speculative indirect
2487	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2488	  support for full protection. The kernel may run slower.
2489
2490config RETHUNK
2491	bool "Enable return-thunks"
2492	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2493	select OBJTOOL if HAVE_OBJTOOL
2494	default y if X86_64
2495	help
2496	  Compile the kernel with the return-thunks compiler option to guard
2497	  against kernel-to-user data leaks by avoiding return speculation.
2498	  Requires a compiler with -mfunction-return=thunk-extern
2499	  support for full protection. The kernel may run slower.
2500
2501config CPU_UNRET_ENTRY
2502	bool "Enable UNRET on kernel entry"
2503	depends on CPU_SUP_AMD && RETHUNK && X86_64
2504	default y
2505	help
2506	  Compile the kernel with support for the retbleed=unret mitigation.
2507
2508config CALL_DEPTH_TRACKING
2509	bool "Mitigate RSB underflow with call depth tracking"
2510	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2511	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2512	select CALL_THUNKS
2513	default y
2514	help
2515	  Compile the kernel with call depth tracking to mitigate the Intel
2516	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
2517	  mitigation is off by default and needs to be enabled on the
2518	  kernel command line via the retbleed=stuff option. For
2519	  non-affected systems the overhead of this option is marginal as
2520	  the call depth tracking is using run-time generated call thunks
2521	  in a compiler generated padding area and call patching. This
2522	  increases text size by ~5%. For non affected systems this space
2523	  is unused. On affected SKL systems this results in a significant
2524	  performance gain over the IBRS mitigation.
2525
2526config CALL_THUNKS_DEBUG
2527	bool "Enable call thunks and call depth tracking debugging"
2528	depends on CALL_DEPTH_TRACKING
2529	select FUNCTION_ALIGNMENT_32B
2530	default n
2531	help
2532	  Enable call/ret counters for imbalance detection and build in
2533	  a noisy dmesg about callthunks generation and call patching for
2534	  trouble shooting. The debug prints need to be enabled on the
2535	  kernel command line with 'debug-callthunks'.
2536	  Only enable this when you are debugging call thunks as this
2537	  creates a noticeable runtime overhead. If unsure say N.
2538
2539config CPU_IBPB_ENTRY
2540	bool "Enable IBPB on kernel entry"
2541	depends on CPU_SUP_AMD && X86_64
2542	default y
2543	help
2544	  Compile the kernel with support for the retbleed=ibpb and
2545	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2546
2547config CPU_IBRS_ENTRY
2548	bool "Enable IBRS on kernel entry"
2549	depends on CPU_SUP_INTEL && X86_64
2550	default y
2551	help
2552	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2553	  This mitigates both spectre_v2 and retbleed at great cost to
2554	  performance.
2555
2556config CPU_SRSO
2557	bool "Mitigate speculative RAS overflow on AMD"
2558	depends on CPU_SUP_AMD && X86_64 && RETHUNK
2559	default y
2560	help
2561	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2562
2563config SLS
2564	bool "Mitigate Straight-Line-Speculation"
2565	depends on CC_HAS_SLS && X86_64
2566	select OBJTOOL if HAVE_OBJTOOL
2567	default n
2568	help
2569	  Compile the kernel with straight-line-speculation options to guard
2570	  against straight line speculation. The kernel image might be slightly
2571	  larger.
2572
2573config GDS_FORCE_MITIGATION
2574	bool "Force GDS Mitigation"
2575	depends on CPU_SUP_INTEL
2576	default n
2577	help
2578	  Gather Data Sampling (GDS) is a hardware vulnerability which allows
2579	  unprivileged speculative access to data which was previously stored in
2580	  vector registers.
2581
2582	  This option is equivalent to setting gather_data_sampling=force on the
2583	  command line. The microcode mitigation is used if present, otherwise
2584	  AVX is disabled as a mitigation. On affected systems that are missing
2585	  the microcode any userspace code that unconditionally uses AVX will
2586	  break with this option set.
2587
2588	  Setting this option on systems not vulnerable to GDS has no effect.
2589
2590	  If in doubt, say N.
2591
2592config MITIGATION_RFDS
2593	bool "RFDS Mitigation"
2594	depends on CPU_SUP_INTEL
2595	default y
2596	help
2597	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2598	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2599	  allows unprivileged speculative access to stale data previously
2600	  stored in floating point, vector and integer registers.
2601	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2602
2603config MITIGATION_SPECTRE_BHI
2604	bool "Mitigate Spectre-BHB (Branch History Injection)"
2605	depends on CPU_SUP_INTEL
2606	default y
2607	help
2608	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2609	  where the branch history buffer is poisoned to speculatively steer
2610	  indirect branches.
2611	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2612
2613endif
2614
2615config ARCH_HAS_ADD_PAGES
2616	def_bool y
2617	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2618
2619menu "Power management and ACPI options"
2620
2621config ARCH_HIBERNATION_HEADER
2622	def_bool y
2623	depends on HIBERNATION
2624
2625source "kernel/power/Kconfig"
2626
2627source "drivers/acpi/Kconfig"
2628
2629config X86_APM_BOOT
2630	def_bool y
2631	depends on APM
2632
2633menuconfig APM
2634	tristate "APM (Advanced Power Management) BIOS support"
2635	depends on X86_32 && PM_SLEEP
2636	help
2637	  APM is a BIOS specification for saving power using several different
2638	  techniques. This is mostly useful for battery powered laptops with
2639	  APM compliant BIOSes. If you say Y here, the system time will be
2640	  reset after a RESUME operation, the /proc/apm device will provide
2641	  battery status information, and user-space programs will receive
2642	  notification of APM "events" (e.g. battery status change).
2643
2644	  If you select "Y" here, you can disable actual use of the APM
2645	  BIOS by passing the "apm=off" option to the kernel at boot time.
2646
2647	  Note that the APM support is almost completely disabled for
2648	  machines with more than one CPU.
2649
2650	  In order to use APM, you will need supporting software. For location
2651	  and more information, read <file:Documentation/power/apm-acpi.rst>
2652	  and the Battery Powered Linux mini-HOWTO, available from
2653	  <http://www.tldp.org/docs.html#howto>.
2654
2655	  This driver does not spin down disk drives (see the hdparm(8)
2656	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2657	  VESA-compliant "green" monitors.
2658
2659	  This driver does not support the TI 4000M TravelMate and the ACER
2660	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2661	  desktop machines also don't have compliant BIOSes, and this driver
2662	  may cause those machines to panic during the boot phase.
2663
2664	  Generally, if you don't have a battery in your machine, there isn't
2665	  much point in using this driver and you should say N. If you get
2666	  random kernel OOPSes or reboots that don't seem to be related to
2667	  anything, try disabling/enabling this option (or disabling/enabling
2668	  APM in your BIOS).
2669
2670	  Some other things you should try when experiencing seemingly random,
2671	  "weird" problems:
2672
2673	  1) make sure that you have enough swap space and that it is
2674	  enabled.
2675	  2) pass the "idle=poll" option to the kernel
2676	  3) switch on floating point emulation in the kernel and pass
2677	  the "no387" option to the kernel
2678	  4) pass the "floppy=nodma" option to the kernel
2679	  5) pass the "mem=4M" option to the kernel (thereby disabling
2680	  all but the first 4 MB of RAM)
2681	  6) make sure that the CPU is not over clocked.
2682	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2683	  8) disable the cache from your BIOS settings
2684	  9) install a fan for the video card or exchange video RAM
2685	  10) install a better fan for the CPU
2686	  11) exchange RAM chips
2687	  12) exchange the motherboard.
2688
2689	  To compile this driver as a module, choose M here: the
2690	  module will be called apm.
2691
2692if APM
2693
2694config APM_IGNORE_USER_SUSPEND
2695	bool "Ignore USER SUSPEND"
2696	help
2697	  This option will ignore USER SUSPEND requests. On machines with a
2698	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2699	  series notebooks, it is necessary to say Y because of a BIOS bug.
2700
2701config APM_DO_ENABLE
2702	bool "Enable PM at boot time"
2703	help
2704	  Enable APM features at boot time. From page 36 of the APM BIOS
2705	  specification: "When disabled, the APM BIOS does not automatically
2706	  power manage devices, enter the Standby State, enter the Suspend
2707	  State, or take power saving steps in response to CPU Idle calls."
2708	  This driver will make CPU Idle calls when Linux is idle (unless this
2709	  feature is turned off -- see "Do CPU IDLE calls", below). This
2710	  should always save battery power, but more complicated APM features
2711	  will be dependent on your BIOS implementation. You may need to turn
2712	  this option off if your computer hangs at boot time when using APM
2713	  support, or if it beeps continuously instead of suspending. Turn
2714	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2715	  T400CDT. This is off by default since most machines do fine without
2716	  this feature.
2717
2718config APM_CPU_IDLE
2719	depends on CPU_IDLE
2720	bool "Make CPU Idle calls when idle"
2721	help
2722	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2723	  On some machines, this can activate improved power savings, such as
2724	  a slowed CPU clock rate, when the machine is idle. These idle calls
2725	  are made after the idle loop has run for some length of time (e.g.,
2726	  333 mS). On some machines, this will cause a hang at boot time or
2727	  whenever the CPU becomes idle. (On machines with more than one CPU,
2728	  this option does nothing.)
2729
2730config APM_DISPLAY_BLANK
2731	bool "Enable console blanking using APM"
2732	help
2733	  Enable console blanking using the APM. Some laptops can use this to
2734	  turn off the LCD backlight when the screen blanker of the Linux
2735	  virtual console blanks the screen. Note that this is only used by
2736	  the virtual console screen blanker, and won't turn off the backlight
2737	  when using the X Window system. This also doesn't have anything to
2738	  do with your VESA-compliant power-saving monitor. Further, this
2739	  option doesn't work for all laptops -- it might not turn off your
2740	  backlight at all, or it might print a lot of errors to the console,
2741	  especially if you are using gpm.
2742
2743config APM_ALLOW_INTS
2744	bool "Allow interrupts during APM BIOS calls"
2745	help
2746	  Normally we disable external interrupts while we are making calls to
2747	  the APM BIOS as a measure to lessen the effects of a badly behaving
2748	  BIOS implementation.  The BIOS should reenable interrupts if it
2749	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2750	  many of the newer IBM Thinkpads.  If you experience hangs when you
2751	  suspend, try setting this to Y.  Otherwise, say N.
2752
2753endif # APM
2754
2755source "drivers/cpufreq/Kconfig"
2756
2757source "drivers/cpuidle/Kconfig"
2758
2759source "drivers/idle/Kconfig"
2760
2761endmenu
2762
2763menu "Bus options (PCI etc.)"
2764
2765choice
2766	prompt "PCI access mode"
2767	depends on X86_32 && PCI
2768	default PCI_GOANY
2769	help
2770	  On PCI systems, the BIOS can be used to detect the PCI devices and
2771	  determine their configuration. However, some old PCI motherboards
2772	  have BIOS bugs and may crash if this is done. Also, some embedded
2773	  PCI-based systems don't have any BIOS at all. Linux can also try to
2774	  detect the PCI hardware directly without using the BIOS.
2775
2776	  With this option, you can specify how Linux should detect the
2777	  PCI devices. If you choose "BIOS", the BIOS will be used,
2778	  if you choose "Direct", the BIOS won't be used, and if you
2779	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2780	  If you choose "Any", the kernel will try MMCONFIG, then the
2781	  direct access method and falls back to the BIOS if that doesn't
2782	  work. If unsure, go with the default, which is "Any".
2783
2784config PCI_GOBIOS
2785	bool "BIOS"
2786
2787config PCI_GOMMCONFIG
2788	bool "MMConfig"
2789
2790config PCI_GODIRECT
2791	bool "Direct"
2792
2793config PCI_GOOLPC
2794	bool "OLPC XO-1"
2795	depends on OLPC
2796
2797config PCI_GOANY
2798	bool "Any"
2799
2800endchoice
2801
2802config PCI_BIOS
2803	def_bool y
2804	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2805
2806# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2807config PCI_DIRECT
2808	def_bool y
2809	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2810
2811config PCI_MMCONFIG
2812	bool "Support mmconfig PCI config space access" if X86_64
2813	default y
2814	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2815	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2816
2817config PCI_OLPC
2818	def_bool y
2819	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2820
2821config PCI_XEN
2822	def_bool y
2823	depends on PCI && XEN
2824
2825config MMCONF_FAM10H
2826	def_bool y
2827	depends on X86_64 && PCI_MMCONFIG && ACPI
2828
2829config PCI_CNB20LE_QUIRK
2830	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2831	depends on PCI
2832	help
2833	  Read the PCI windows out of the CNB20LE host bridge. This allows
2834	  PCI hotplug to work on systems with the CNB20LE chipset which do
2835	  not have ACPI.
2836
2837	  There's no public spec for this chipset, and this functionality
2838	  is known to be incomplete.
2839
2840	  You should say N unless you know you need this.
2841
2842config ISA_BUS
2843	bool "ISA bus support on modern systems" if EXPERT
2844	help
2845	  Expose ISA bus device drivers and options available for selection and
2846	  configuration. Enable this option if your target machine has an ISA
2847	  bus. ISA is an older system, displaced by PCI and newer bus
2848	  architectures -- if your target machine is modern, it probably does
2849	  not have an ISA bus.
2850
2851	  If unsure, say N.
2852
2853# x86_64 have no ISA slots, but can have ISA-style DMA.
2854config ISA_DMA_API
2855	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2856	default y
2857	help
2858	  Enables ISA-style DMA support for devices requiring such controllers.
2859	  If unsure, say Y.
2860
2861if X86_32
2862
2863config ISA
2864	bool "ISA support"
2865	help
2866	  Find out whether you have ISA slots on your motherboard.  ISA is the
2867	  name of a bus system, i.e. the way the CPU talks to the other stuff
2868	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2869	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2870	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2871
2872config SCx200
2873	tristate "NatSemi SCx200 support"
2874	help
2875	  This provides basic support for National Semiconductor's
2876	  (now AMD's) Geode processors.  The driver probes for the
2877	  PCI-IDs of several on-chip devices, so its a good dependency
2878	  for other scx200_* drivers.
2879
2880	  If compiled as a module, the driver is named scx200.
2881
2882config SCx200HR_TIMER
2883	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2884	depends on SCx200
2885	default y
2886	help
2887	  This driver provides a clocksource built upon the on-chip
2888	  27MHz high-resolution timer.  Its also a workaround for
2889	  NSC Geode SC-1100's buggy TSC, which loses time when the
2890	  processor goes idle (as is done by the scheduler).  The
2891	  other workaround is idle=poll boot option.
2892
2893config OLPC
2894	bool "One Laptop Per Child support"
2895	depends on !X86_PAE
2896	select GPIOLIB
2897	select OF
2898	select OF_PROMTREE
2899	select IRQ_DOMAIN
2900	select OLPC_EC
2901	help
2902	  Add support for detecting the unique features of the OLPC
2903	  XO hardware.
2904
2905config OLPC_XO1_PM
2906	bool "OLPC XO-1 Power Management"
2907	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2908	help
2909	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2910
2911config OLPC_XO1_RTC
2912	bool "OLPC XO-1 Real Time Clock"
2913	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2914	help
2915	  Add support for the XO-1 real time clock, which can be used as a
2916	  programmable wakeup source.
2917
2918config OLPC_XO1_SCI
2919	bool "OLPC XO-1 SCI extras"
2920	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2921	depends on INPUT=y
2922	select POWER_SUPPLY
2923	help
2924	  Add support for SCI-based features of the OLPC XO-1 laptop:
2925	   - EC-driven system wakeups
2926	   - Power button
2927	   - Ebook switch
2928	   - Lid switch
2929	   - AC adapter status updates
2930	   - Battery status updates
2931
2932config OLPC_XO15_SCI
2933	bool "OLPC XO-1.5 SCI extras"
2934	depends on OLPC && ACPI
2935	select POWER_SUPPLY
2936	help
2937	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2938	   - EC-driven system wakeups
2939	   - AC adapter status updates
2940	   - Battery status updates
2941
2942config ALIX
2943	bool "PCEngines ALIX System Support (LED setup)"
2944	select GPIOLIB
2945	help
2946	  This option enables system support for the PCEngines ALIX.
2947	  At present this just sets up LEDs for GPIO control on
2948	  ALIX2/3/6 boards.  However, other system specific setup should
2949	  get added here.
2950
2951	  Note: You must still enable the drivers for GPIO and LED support
2952	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2953
2954	  Note: You have to set alix.force=1 for boards with Award BIOS.
2955
2956config NET5501
2957	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2958	select GPIOLIB
2959	help
2960	  This option enables system support for the Soekris Engineering net5501.
2961
2962config GEOS
2963	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2964	select GPIOLIB
2965	depends on DMI
2966	help
2967	  This option enables system support for the Traverse Technologies GEOS.
2968
2969config TS5500
2970	bool "Technologic Systems TS-5500 platform support"
2971	depends on MELAN
2972	select CHECK_SIGNATURE
2973	select NEW_LEDS
2974	select LEDS_CLASS
2975	help
2976	  This option enables system support for the Technologic Systems TS-5500.
2977
2978endif # X86_32
2979
2980config AMD_NB
2981	def_bool y
2982	depends on CPU_SUP_AMD && PCI
2983
2984endmenu
2985
2986menu "Binary Emulations"
2987
2988config IA32_EMULATION
2989	bool "IA32 Emulation"
2990	depends on X86_64
2991	select ARCH_WANT_OLD_COMPAT_IPC
2992	select BINFMT_ELF
2993	select COMPAT_OLD_SIGACTION
2994	help
2995	  Include code to run legacy 32-bit programs under a
2996	  64-bit kernel. You should likely turn this on, unless you're
2997	  100% sure that you don't have any 32-bit programs left.
2998
2999config X86_X32_ABI
3000	bool "x32 ABI for 64-bit mode"
3001	depends on X86_64
3002	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3003	# compressed debug sections to x86_x32 properly:
3004	# https://github.com/ClangBuiltLinux/linux/issues/514
3005	# https://github.com/ClangBuiltLinux/linux/issues/1141
3006	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3007	help
3008	  Include code to run binaries for the x32 native 32-bit ABI
3009	  for 64-bit processors.  An x32 process gets access to the
3010	  full 64-bit register file and wide data path while leaving
3011	  pointers at 32 bits for smaller memory footprint.
3012
3013config COMPAT_32
3014	def_bool y
3015	depends on IA32_EMULATION || X86_32
3016	select HAVE_UID16
3017	select OLD_SIGSUSPEND3
3018
3019config COMPAT
3020	def_bool y
3021	depends on IA32_EMULATION || X86_X32_ABI
3022
3023config COMPAT_FOR_U64_ALIGNMENT
3024	def_bool y
3025	depends on COMPAT
3026
3027endmenu
3028
3029config HAVE_ATOMIC_IOMAP
3030	def_bool y
3031	depends on X86_32
3032
3033source "arch/x86/kvm/Kconfig"
3034
3035source "arch/x86/Kconfig.assembler"
3036