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_USE_CMPXCHG_LOCKREF
31	select HAVE_ARCH_SOFT_DIRTY
32	select MODULES_USE_ELF_RELA
33	select NEED_DMA_MAP_STATE
34	select SWIOTLB
35	select ARCH_HAS_ELFCORE_COMPAT
36	select ZONE_DMA32
37
38config FORCE_DYNAMIC_FTRACE
39	def_bool y
40	depends on X86_32
41	depends on FUNCTION_TRACER
42	select DYNAMIC_FTRACE
43	help
44	  We keep the static function tracing (!DYNAMIC_FTRACE) around
45	  in order to test the non static function tracing in the
46	  generic code, as other architectures still use it. But we
47	  only need to keep it around for x86_64. No need to keep it
48	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
49#
50# Arch settings
51#
52# ( Note that options that are marked 'if X86_64' could in principle be
53#   ported to 32-bit as well. )
54#
55config X86
56	def_bool y
57	#
58	# Note: keep this list sorted alphabetically
59	#
60	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
61	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
62	select ARCH_32BIT_OFF_T			if X86_32
63	select ARCH_CLOCKSOURCE_INIT
64	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
65	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
66	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
67	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
68	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
69	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
70	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
71	select ARCH_HAS_CACHE_LINE_SIZE
72	select ARCH_HAS_CURRENT_STACK_POINTER
73	select ARCH_HAS_DEBUG_VIRTUAL
74	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
75	select ARCH_HAS_DEVMEM_IS_ALLOWED
76	select ARCH_HAS_EARLY_DEBUG		if KGDB
77	select ARCH_HAS_ELF_RANDOMIZE
78	select ARCH_HAS_FAST_MULTIPLIER
79	select ARCH_HAS_FORTIFY_SOURCE
80	select ARCH_HAS_GCOV_PROFILE_ALL
81	select ARCH_HAS_KCOV			if X86_64
82	select ARCH_HAS_MEM_ENCRYPT
83	select ARCH_HAS_MEMBARRIER_SYNC_CORE
84	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
85	select ARCH_HAS_PMEM_API		if X86_64
86	select ARCH_HAS_PTE_DEVMAP		if X86_64
87	select ARCH_HAS_PTE_SPECIAL
88	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
89	select ARCH_HAS_COPY_MC			if X86_64
90	select ARCH_HAS_SET_MEMORY
91	select ARCH_HAS_SET_DIRECT_MAP
92	select ARCH_HAS_STRICT_KERNEL_RWX
93	select ARCH_HAS_STRICT_MODULE_RWX
94	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
95	select ARCH_HAS_SYSCALL_WRAPPER
96	select ARCH_HAS_UBSAN_SANITIZE_ALL
97	select ARCH_HAS_VM_GET_PAGE_PROT
98	select ARCH_HAS_DEBUG_WX
99	select ARCH_HAS_ZONE_DMA_SET if EXPERT
100	select ARCH_HAVE_NMI_SAFE_CMPXCHG
101	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
102	select ARCH_MIGHT_HAVE_PC_PARPORT
103	select ARCH_MIGHT_HAVE_PC_SERIO
104	select ARCH_STACKWALK
105	select ARCH_SUPPORTS_ACPI
106	select ARCH_SUPPORTS_ATOMIC_RMW
107	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
108	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
109	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
110	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
111	select ARCH_SUPPORTS_LTO_CLANG
112	select ARCH_SUPPORTS_LTO_CLANG_THIN
113	select ARCH_USE_BUILTIN_BSWAP
114	select ARCH_USE_MEMTEST
115	select ARCH_USE_QUEUED_RWLOCKS
116	select ARCH_USE_QUEUED_SPINLOCKS
117	select ARCH_USE_SYM_ANNOTATIONS
118	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
119	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
120	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
121	select ARCH_WANTS_NO_INSTR
122	select ARCH_WANT_GENERAL_HUGETLB
123	select ARCH_WANT_HUGE_PMD_SHARE
124	select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP	if X86_64
125	select ARCH_WANT_LD_ORPHAN_WARN
126	select ARCH_WANTS_THP_SWAP		if X86_64
127	select ARCH_HAS_PARANOID_L1D_FLUSH
128	select BUILDTIME_TABLE_SORT
129	select CLKEVT_I8253
130	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
131	select CLOCKSOURCE_WATCHDOG
132	select DCACHE_WORD_ACCESS
133	select DYNAMIC_SIGFRAME
134	select EDAC_ATOMIC_SCRUB
135	select EDAC_SUPPORT
136	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
137	select GENERIC_CLOCKEVENTS_MIN_ADJUST
138	select GENERIC_CMOS_UPDATE
139	select GENERIC_CPU_AUTOPROBE
140	select GENERIC_CPU_VULNERABILITIES
141	select GENERIC_EARLY_IOREMAP
142	select GENERIC_ENTRY
143	select GENERIC_IOMAP
144	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
145	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
146	select GENERIC_IRQ_MIGRATION		if SMP
147	select GENERIC_IRQ_PROBE
148	select GENERIC_IRQ_RESERVATION_MODE
149	select GENERIC_IRQ_SHOW
150	select GENERIC_PENDING_IRQ		if SMP
151	select GENERIC_PTDUMP
152	select GENERIC_SMP_IDLE_THREAD
153	select GENERIC_TIME_VSYSCALL
154	select GENERIC_GETTIMEOFDAY
155	select GENERIC_VDSO_TIME_NS
156	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
157	select HARDIRQS_SW_RESEND
158	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
159	select HAVE_ACPI_APEI			if ACPI
160	select HAVE_ACPI_APEI_NMI		if ACPI
161	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
162	select HAVE_ARCH_AUDITSYSCALL
163	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
164	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
165	select HAVE_ARCH_JUMP_LABEL
166	select HAVE_ARCH_JUMP_LABEL_RELATIVE
167	select HAVE_ARCH_KASAN			if X86_64
168	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
169	select HAVE_ARCH_KFENCE
170	select HAVE_ARCH_KGDB
171	select HAVE_ARCH_MMAP_RND_BITS		if MMU
172	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
173	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
174	select HAVE_ARCH_PREL32_RELOCATIONS
175	select HAVE_ARCH_SECCOMP_FILTER
176	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
177	select HAVE_ARCH_STACKLEAK
178	select HAVE_ARCH_TRACEHOOK
179	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
180	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
181	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
182	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
183	select HAVE_ARCH_VMAP_STACK		if X86_64
184	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
185	select HAVE_ARCH_WITHIN_STACK_FRAMES
186	select HAVE_ASM_MODVERSIONS
187	select HAVE_CMPXCHG_DOUBLE
188	select HAVE_CMPXCHG_LOCAL
189	select HAVE_CONTEXT_TRACKING		if X86_64
190	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
191	select HAVE_C_RECORDMCOUNT
192	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
193	select HAVE_BUILDTIME_MCOUNT_SORT
194	select HAVE_DEBUG_KMEMLEAK
195	select HAVE_DMA_CONTIGUOUS
196	select HAVE_DYNAMIC_FTRACE
197	select HAVE_DYNAMIC_FTRACE_WITH_REGS
198	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
199	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
200	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
201	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
202	select HAVE_EBPF_JIT
203	select HAVE_EFFICIENT_UNALIGNED_ACCESS
204	select HAVE_EISA
205	select HAVE_EXIT_THREAD
206	select HAVE_FAST_GUP
207	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
208	select HAVE_FTRACE_MCOUNT_RECORD
209	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
210	select HAVE_FUNCTION_TRACER
211	select HAVE_GCC_PLUGINS
212	select HAVE_HW_BREAKPOINT
213	select HAVE_IOREMAP_PROT
214	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
215	select HAVE_IRQ_TIME_ACCOUNTING
216	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
217	select HAVE_KERNEL_BZIP2
218	select HAVE_KERNEL_GZIP
219	select HAVE_KERNEL_LZ4
220	select HAVE_KERNEL_LZMA
221	select HAVE_KERNEL_LZO
222	select HAVE_KERNEL_XZ
223	select HAVE_KERNEL_ZSTD
224	select HAVE_KPROBES
225	select HAVE_KPROBES_ON_FTRACE
226	select HAVE_FUNCTION_ERROR_INJECTION
227	select HAVE_KRETPROBES
228	select HAVE_RETHOOK
229	select HAVE_KVM
230	select HAVE_LIVEPATCH			if X86_64
231	select HAVE_MIXED_BREAKPOINTS_REGS
232	select HAVE_MOD_ARCH_SPECIFIC
233	select HAVE_MOVE_PMD
234	select HAVE_MOVE_PUD
235	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
236	select HAVE_NMI
237	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
238	select HAVE_OBJTOOL			if X86_64
239	select HAVE_OPTPROBES
240	select HAVE_PCSPKR_PLATFORM
241	select HAVE_PERF_EVENTS
242	select HAVE_PERF_EVENTS_NMI
243	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
244	select HAVE_PCI
245	select HAVE_PERF_REGS
246	select HAVE_PERF_USER_STACK_DUMP
247	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
248	select MMU_GATHER_MERGE_VMAS
249	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
250	select HAVE_REGS_AND_STACK_ACCESS_API
251	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
252	select HAVE_FUNCTION_ARG_ACCESS_API
253	select HAVE_SETUP_PER_CPU_AREA
254	select HAVE_SOFTIRQ_ON_OWN_STACK
255	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
256	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
257	select HAVE_STATIC_CALL
258	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
259	select HAVE_PREEMPT_DYNAMIC_CALL
260	select HAVE_RSEQ
261	select HAVE_SYSCALL_TRACEPOINTS
262	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
263	select HAVE_UNSTABLE_SCHED_CLOCK
264	select HAVE_USER_RETURN_NOTIFIER
265	select HAVE_GENERIC_VDSO
266	select HOTPLUG_SMT			if SMP
267	select IRQ_FORCED_THREADING
268	select NEED_PER_CPU_EMBED_FIRST_CHUNK
269	select NEED_PER_CPU_PAGE_FIRST_CHUNK
270	select NEED_SG_DMA_LENGTH
271	select PCI_DOMAINS			if PCI
272	select PCI_LOCKLESS_CONFIG		if PCI
273	select PERF_EVENTS
274	select RTC_LIB
275	select RTC_MC146818_LIB
276	select SPARSE_IRQ
277	select SRCU
278	select SYSCTL_EXCEPTION_TRACE
279	select THREAD_INFO_IN_TASK
280	select TRACE_IRQFLAGS_SUPPORT
281	select TRACE_IRQFLAGS_NMI_SUPPORT
282	select USER_STACKTRACE_SUPPORT
283	select VIRT_TO_BUS
284	select HAVE_ARCH_KCSAN			if X86_64
285	select X86_FEATURE_NAMES		if PROC_FS
286	select PROC_PID_ARCH_STATUS		if PROC_FS
287	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
288	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
289
290config INSTRUCTION_DECODER
291	def_bool y
292	depends on KPROBES || PERF_EVENTS || UPROBES
293
294config OUTPUT_FORMAT
295	string
296	default "elf32-i386" if X86_32
297	default "elf64-x86-64" if X86_64
298
299config LOCKDEP_SUPPORT
300	def_bool y
301
302config STACKTRACE_SUPPORT
303	def_bool y
304
305config MMU
306	def_bool y
307
308config ARCH_MMAP_RND_BITS_MIN
309	default 28 if 64BIT
310	default 8
311
312config ARCH_MMAP_RND_BITS_MAX
313	default 32 if 64BIT
314	default 16
315
316config ARCH_MMAP_RND_COMPAT_BITS_MIN
317	default 8
318
319config ARCH_MMAP_RND_COMPAT_BITS_MAX
320	default 16
321
322config SBUS
323	bool
324
325config GENERIC_ISA_DMA
326	def_bool y
327	depends on ISA_DMA_API
328
329config GENERIC_BUG
330	def_bool y
331	depends on BUG
332	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
333
334config GENERIC_BUG_RELATIVE_POINTERS
335	bool
336
337config ARCH_MAY_HAVE_PC_FDC
338	def_bool y
339	depends on ISA_DMA_API
340
341config GENERIC_CALIBRATE_DELAY
342	def_bool y
343
344config ARCH_HAS_CPU_RELAX
345	def_bool y
346
347config ARCH_HIBERNATION_POSSIBLE
348	def_bool y
349
350config ARCH_NR_GPIO
351	int
352	default 1024 if X86_64
353	default 512
354
355config ARCH_SUSPEND_POSSIBLE
356	def_bool y
357
358config AUDIT_ARCH
359	def_bool y if X86_64
360
361config KASAN_SHADOW_OFFSET
362	hex
363	depends on KASAN
364	default 0xdffffc0000000000
365
366config HAVE_INTEL_TXT
367	def_bool y
368	depends on INTEL_IOMMU && ACPI
369
370config X86_32_SMP
371	def_bool y
372	depends on X86_32 && SMP
373
374config X86_64_SMP
375	def_bool y
376	depends on X86_64 && SMP
377
378config ARCH_SUPPORTS_UPROBES
379	def_bool y
380
381config FIX_EARLYCON_MEM
382	def_bool y
383
384config DYNAMIC_PHYSICAL_MASK
385	bool
386
387config PGTABLE_LEVELS
388	int
389	default 5 if X86_5LEVEL
390	default 4 if X86_64
391	default 3 if X86_PAE
392	default 2
393
394config CC_HAS_SANE_STACKPROTECTOR
395	bool
396	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
397	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
398	help
399	  We have to make sure stack protector is unconditionally disabled if
400	  the compiler produces broken code or if it does not let us control
401	  the segment on 32-bit kernels.
402
403menu "Processor type and features"
404
405config SMP
406	bool "Symmetric multi-processing support"
407	help
408	  This enables support for systems with more than one CPU. If you have
409	  a system with only one CPU, say N. If you have a system with more
410	  than one CPU, say Y.
411
412	  If you say N here, the kernel will run on uni- and multiprocessor
413	  machines, but will use only one CPU of a multiprocessor machine. If
414	  you say Y here, the kernel will run on many, but not all,
415	  uniprocessor machines. On a uniprocessor machine, the kernel
416	  will run faster if you say N here.
417
418	  Note that if you say Y here and choose architecture "586" or
419	  "Pentium" under "Processor family", the kernel will not work on 486
420	  architectures. Similarly, multiprocessor kernels for the "PPro"
421	  architecture may not work on all Pentium based boards.
422
423	  People using multiprocessor machines who say Y here should also say
424	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
425	  Management" code will be disabled if you say Y here.
426
427	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
428	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
429	  <http://www.tldp.org/docs.html#howto>.
430
431	  If you don't know what to do here, say N.
432
433config X86_FEATURE_NAMES
434	bool "Processor feature human-readable names" if EMBEDDED
435	default y
436	help
437	  This option compiles in a table of x86 feature bits and corresponding
438	  names.  This is required to support /proc/cpuinfo and a few kernel
439	  messages.  You can disable this to save space, at the expense of
440	  making those few kernel messages show numeric feature bits instead.
441
442	  If in doubt, say Y.
443
444config X86_X2APIC
445	bool "Support x2apic"
446	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
447	help
448	  This enables x2apic support on CPUs that have this feature.
449
450	  This allows 32-bit apic IDs (so it can support very large systems),
451	  and accesses the local apic via MSRs not via mmio.
452
453	  If you don't know what to do here, say N.
454
455config X86_MPPARSE
456	bool "Enable MPS table" if ACPI
457	default y
458	depends on X86_LOCAL_APIC
459	help
460	  For old smp systems that do not have proper acpi support. Newer systems
461	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
462
463config GOLDFISH
464	def_bool y
465	depends on X86_GOLDFISH
466
467config X86_CPU_RESCTRL
468	bool "x86 CPU resource control support"
469	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
470	select KERNFS
471	select PROC_CPU_RESCTRL		if PROC_FS
472	help
473	  Enable x86 CPU resource control support.
474
475	  Provide support for the allocation and monitoring of system resources
476	  usage by the CPU.
477
478	  Intel calls this Intel Resource Director Technology
479	  (Intel(R) RDT). More information about RDT can be found in the
480	  Intel x86 Architecture Software Developer Manual.
481
482	  AMD calls this AMD Platform Quality of Service (AMD QoS).
483	  More information about AMD QoS can be found in the AMD64 Technology
484	  Platform Quality of Service Extensions manual.
485
486	  Say N if unsure.
487
488if X86_32
489config X86_BIGSMP
490	bool "Support for big SMP systems with more than 8 CPUs"
491	depends on SMP
492	help
493	  This option is needed for the systems that have more than 8 CPUs.
494
495config X86_EXTENDED_PLATFORM
496	bool "Support for extended (non-PC) x86 platforms"
497	default y
498	help
499	  If you disable this option then the kernel will only support
500	  standard PC platforms. (which covers the vast majority of
501	  systems out there.)
502
503	  If you enable this option then you'll be able to select support
504	  for the following (non-PC) 32 bit x86 platforms:
505		Goldfish (Android emulator)
506		AMD Elan
507		RDC R-321x SoC
508		SGI 320/540 (Visual Workstation)
509		STA2X11-based (e.g. Northville)
510		Moorestown MID devices
511
512	  If you have one of these systems, or if you want to build a
513	  generic distribution kernel, say Y here - otherwise say N.
514endif # X86_32
515
516if X86_64
517config X86_EXTENDED_PLATFORM
518	bool "Support for extended (non-PC) x86 platforms"
519	default y
520	help
521	  If you disable this option then the kernel will only support
522	  standard PC platforms. (which covers the vast majority of
523	  systems out there.)
524
525	  If you enable this option then you'll be able to select support
526	  for the following (non-PC) 64 bit x86 platforms:
527		Numascale NumaChip
528		ScaleMP vSMP
529		SGI Ultraviolet
530
531	  If you have one of these systems, or if you want to build a
532	  generic distribution kernel, say Y here - otherwise say N.
533endif # X86_64
534# This is an alphabetically sorted list of 64 bit extended platforms
535# Please maintain the alphabetic order if and when there are additions
536config X86_NUMACHIP
537	bool "Numascale NumaChip"
538	depends on X86_64
539	depends on X86_EXTENDED_PLATFORM
540	depends on NUMA
541	depends on SMP
542	depends on X86_X2APIC
543	depends on PCI_MMCONFIG
544	help
545	  Adds support for Numascale NumaChip large-SMP systems. Needed to
546	  enable more than ~168 cores.
547	  If you don't have one of these, you should say N here.
548
549config X86_VSMP
550	bool "ScaleMP vSMP"
551	select HYPERVISOR_GUEST
552	select PARAVIRT
553	depends on X86_64 && PCI
554	depends on X86_EXTENDED_PLATFORM
555	depends on SMP
556	help
557	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
558	  supposed to run on these EM64T-based machines.  Only choose this option
559	  if you have one of these machines.
560
561config X86_UV
562	bool "SGI Ultraviolet"
563	depends on X86_64
564	depends on X86_EXTENDED_PLATFORM
565	depends on NUMA
566	depends on EFI
567	depends on KEXEC_CORE
568	depends on X86_X2APIC
569	depends on PCI
570	help
571	  This option is needed in order to support SGI Ultraviolet systems.
572	  If you don't have one of these, you should say N here.
573
574# Following is an alphabetically sorted list of 32 bit extended platforms
575# Please maintain the alphabetic order if and when there are additions
576
577config X86_GOLDFISH
578	bool "Goldfish (Virtual Platform)"
579	depends on X86_EXTENDED_PLATFORM
580	help
581	  Enable support for the Goldfish virtual platform used primarily
582	  for Android development. Unless you are building for the Android
583	  Goldfish emulator say N here.
584
585config X86_INTEL_CE
586	bool "CE4100 TV platform"
587	depends on PCI
588	depends on PCI_GODIRECT
589	depends on X86_IO_APIC
590	depends on X86_32
591	depends on X86_EXTENDED_PLATFORM
592	select X86_REBOOTFIXUPS
593	select OF
594	select OF_EARLY_FLATTREE
595	help
596	  Select for the Intel CE media processor (CE4100) SOC.
597	  This option compiles in support for the CE4100 SOC for settop
598	  boxes and media devices.
599
600config X86_INTEL_MID
601	bool "Intel MID platform support"
602	depends on X86_EXTENDED_PLATFORM
603	depends on X86_PLATFORM_DEVICES
604	depends on PCI
605	depends on X86_64 || (PCI_GOANY && X86_32)
606	depends on X86_IO_APIC
607	select I2C
608	select DW_APB_TIMER
609	select INTEL_SCU_PCI
610	help
611	  Select to build a kernel capable of supporting Intel MID (Mobile
612	  Internet Device) platform systems which do not have the PCI legacy
613	  interfaces. If you are building for a PC class system say N here.
614
615	  Intel MID platforms are based on an Intel processor and chipset which
616	  consume less power than most of the x86 derivatives.
617
618config X86_INTEL_QUARK
619	bool "Intel Quark platform support"
620	depends on X86_32
621	depends on X86_EXTENDED_PLATFORM
622	depends on X86_PLATFORM_DEVICES
623	depends on X86_TSC
624	depends on PCI
625	depends on PCI_GOANY
626	depends on X86_IO_APIC
627	select IOSF_MBI
628	select INTEL_IMR
629	select COMMON_CLK
630	help
631	  Select to include support for Quark X1000 SoC.
632	  Say Y here if you have a Quark based system such as the Arduino
633	  compatible Intel Galileo.
634
635config X86_INTEL_LPSS
636	bool "Intel Low Power Subsystem Support"
637	depends on X86 && ACPI && PCI
638	select COMMON_CLK
639	select PINCTRL
640	select IOSF_MBI
641	help
642	  Select to build support for Intel Low Power Subsystem such as
643	  found on Intel Lynxpoint PCH. Selecting this option enables
644	  things like clock tree (common clock framework) and pincontrol
645	  which are needed by the LPSS peripheral drivers.
646
647config X86_AMD_PLATFORM_DEVICE
648	bool "AMD ACPI2Platform devices support"
649	depends on ACPI
650	select COMMON_CLK
651	select PINCTRL
652	help
653	  Select to interpret AMD specific ACPI device to platform device
654	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
655	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
656	  implemented under PINCTRL subsystem.
657
658config IOSF_MBI
659	tristate "Intel SoC IOSF Sideband support for SoC platforms"
660	depends on PCI
661	help
662	  This option enables sideband register access support for Intel SoC
663	  platforms. On these platforms the IOSF sideband is used in lieu of
664	  MSR's for some register accesses, mostly but not limited to thermal
665	  and power. Drivers may query the availability of this device to
666	  determine if they need the sideband in order to work on these
667	  platforms. The sideband is available on the following SoC products.
668	  This list is not meant to be exclusive.
669	   - BayTrail
670	   - Braswell
671	   - Quark
672
673	  You should say Y if you are running a kernel on one of these SoC's.
674
675config IOSF_MBI_DEBUG
676	bool "Enable IOSF sideband access through debugfs"
677	depends on IOSF_MBI && DEBUG_FS
678	help
679	  Select this option to expose the IOSF sideband access registers (MCR,
680	  MDR, MCRX) through debugfs to write and read register information from
681	  different units on the SoC. This is most useful for obtaining device
682	  state information for debug and analysis. As this is a general access
683	  mechanism, users of this option would have specific knowledge of the
684	  device they want to access.
685
686	  If you don't require the option or are in doubt, say N.
687
688config X86_RDC321X
689	bool "RDC R-321x SoC"
690	depends on X86_32
691	depends on X86_EXTENDED_PLATFORM
692	select M486
693	select X86_REBOOTFIXUPS
694	help
695	  This option is needed for RDC R-321x system-on-chip, also known
696	  as R-8610-(G).
697	  If you don't have one of these chips, you should say N here.
698
699config X86_32_NON_STANDARD
700	bool "Support non-standard 32-bit SMP architectures"
701	depends on X86_32 && SMP
702	depends on X86_EXTENDED_PLATFORM
703	help
704	  This option compiles in the bigsmp and STA2X11 default
705	  subarchitectures.  It is intended for a generic binary
706	  kernel. If you select them all, kernel will probe it one by
707	  one and will fallback to default.
708
709# Alphabetically sorted list of Non standard 32 bit platforms
710
711config X86_SUPPORTS_MEMORY_FAILURE
712	def_bool y
713	# MCE code calls memory_failure():
714	depends on X86_MCE
715	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
716	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
717	depends on X86_64 || !SPARSEMEM
718	select ARCH_SUPPORTS_MEMORY_FAILURE
719
720config STA2X11
721	bool "STA2X11 Companion Chip Support"
722	depends on X86_32_NON_STANDARD && PCI
723	select SWIOTLB
724	select MFD_STA2X11
725	select GPIOLIB
726	help
727	  This adds support for boards based on the STA2X11 IO-Hub,
728	  a.k.a. "ConneXt". The chip is used in place of the standard
729	  PC chipset, so all "standard" peripherals are missing. If this
730	  option is selected the kernel will still be able to boot on
731	  standard PC machines.
732
733config X86_32_IRIS
734	tristate "Eurobraille/Iris poweroff module"
735	depends on X86_32
736	help
737	  The Iris machines from EuroBraille do not have APM or ACPI support
738	  to shut themselves down properly.  A special I/O sequence is
739	  needed to do so, which is what this module does at
740	  kernel shutdown.
741
742	  This is only for Iris machines from EuroBraille.
743
744	  If unused, say N.
745
746config SCHED_OMIT_FRAME_POINTER
747	def_bool y
748	prompt "Single-depth WCHAN output"
749	depends on X86
750	help
751	  Calculate simpler /proc/<PID>/wchan values. If this option
752	  is disabled then wchan values will recurse back to the
753	  caller function. This provides more accurate wchan values,
754	  at the expense of slightly more scheduling overhead.
755
756	  If in doubt, say "Y".
757
758menuconfig HYPERVISOR_GUEST
759	bool "Linux guest support"
760	help
761	  Say Y here to enable options for running Linux under various hyper-
762	  visors. This option enables basic hypervisor detection and platform
763	  setup.
764
765	  If you say N, all options in this submenu will be skipped and
766	  disabled, and Linux guest support won't be built in.
767
768if HYPERVISOR_GUEST
769
770config PARAVIRT
771	bool "Enable paravirtualization code"
772	depends on HAVE_STATIC_CALL
773	help
774	  This changes the kernel so it can modify itself when it is run
775	  under a hypervisor, potentially improving performance significantly
776	  over full virtualization.  However, when run without a hypervisor
777	  the kernel is theoretically slower and slightly larger.
778
779config PARAVIRT_XXL
780	bool
781
782config PARAVIRT_DEBUG
783	bool "paravirt-ops debugging"
784	depends on PARAVIRT && DEBUG_KERNEL
785	help
786	  Enable to debug paravirt_ops internals.  Specifically, BUG if
787	  a paravirt_op is missing when it is called.
788
789config PARAVIRT_SPINLOCKS
790	bool "Paravirtualization layer for spinlocks"
791	depends on PARAVIRT && SMP
792	help
793	  Paravirtualized spinlocks allow a pvops backend to replace the
794	  spinlock implementation with something virtualization-friendly
795	  (for example, block the virtual CPU rather than spinning).
796
797	  It has a minimal impact on native kernels and gives a nice performance
798	  benefit on paravirtualized KVM / Xen kernels.
799
800	  If you are unsure how to answer this question, answer Y.
801
802config X86_HV_CALLBACK_VECTOR
803	def_bool n
804
805source "arch/x86/xen/Kconfig"
806
807config KVM_GUEST
808	bool "KVM Guest support (including kvmclock)"
809	depends on PARAVIRT
810	select PARAVIRT_CLOCK
811	select ARCH_CPUIDLE_HALTPOLL
812	select X86_HV_CALLBACK_VECTOR
813	default y
814	help
815	  This option enables various optimizations for running under the KVM
816	  hypervisor. It includes a paravirtualized clock, so that instead
817	  of relying on a PIT (or probably other) emulation by the
818	  underlying device model, the host provides the guest with
819	  timing infrastructure such as time of day, and system time
820
821config ARCH_CPUIDLE_HALTPOLL
822	def_bool n
823	prompt "Disable host haltpoll when loading haltpoll driver"
824	help
825	  If virtualized under KVM, disable host haltpoll.
826
827config PVH
828	bool "Support for running PVH guests"
829	help
830	  This option enables the PVH entry point for guest virtual machines
831	  as specified in the x86/HVM direct boot ABI.
832
833config PARAVIRT_TIME_ACCOUNTING
834	bool "Paravirtual steal time accounting"
835	depends on PARAVIRT
836	help
837	  Select this option to enable fine granularity task steal time
838	  accounting. Time spent executing other tasks in parallel with
839	  the current vCPU is discounted from the vCPU power. To account for
840	  that, there can be a small performance impact.
841
842	  If in doubt, say N here.
843
844config PARAVIRT_CLOCK
845	bool
846
847config JAILHOUSE_GUEST
848	bool "Jailhouse non-root cell support"
849	depends on X86_64 && PCI
850	select X86_PM_TIMER
851	help
852	  This option allows to run Linux as guest in a Jailhouse non-root
853	  cell. You can leave this option disabled if you only want to start
854	  Jailhouse and run Linux afterwards in the root cell.
855
856config ACRN_GUEST
857	bool "ACRN Guest support"
858	depends on X86_64
859	select X86_HV_CALLBACK_VECTOR
860	help
861	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
862	  a flexible, lightweight reference open-source hypervisor, built with
863	  real-time and safety-criticality in mind. It is built for embedded
864	  IOT with small footprint and real-time features. More details can be
865	  found in https://projectacrn.org/.
866
867config INTEL_TDX_GUEST
868	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
869	depends on X86_64 && CPU_SUP_INTEL
870	depends on X86_X2APIC
871	select ARCH_HAS_CC_PLATFORM
872	select X86_MEM_ENCRYPT
873	select X86_MCE
874	help
875	  Support running as a guest under Intel TDX.  Without this support,
876	  the guest kernel can not boot or run under TDX.
877	  TDX includes memory encryption and integrity capabilities
878	  which protect the confidentiality and integrity of guest
879	  memory contents and CPU state. TDX guests are protected from
880	  some attacks from the VMM.
881
882endif # HYPERVISOR_GUEST
883
884source "arch/x86/Kconfig.cpu"
885
886config HPET_TIMER
887	def_bool X86_64
888	prompt "HPET Timer Support" if X86_32
889	help
890	  Use the IA-PC HPET (High Precision Event Timer) to manage
891	  time in preference to the PIT and RTC, if a HPET is
892	  present.
893	  HPET is the next generation timer replacing legacy 8254s.
894	  The HPET provides a stable time base on SMP
895	  systems, unlike the TSC, but it is more expensive to access,
896	  as it is off-chip.  The interface used is documented
897	  in the HPET spec, revision 1.
898
899	  You can safely choose Y here.  However, HPET will only be
900	  activated if the platform and the BIOS support this feature.
901	  Otherwise the 8254 will be used for timing services.
902
903	  Choose N to continue using the legacy 8254 timer.
904
905config HPET_EMULATE_RTC
906	def_bool y
907	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
908
909# Mark as expert because too many people got it wrong.
910# The code disables itself when not needed.
911config DMI
912	default y
913	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
914	bool "Enable DMI scanning" if EXPERT
915	help
916	  Enabled scanning of DMI to identify machine quirks. Say Y
917	  here unless you have verified that your setup is not
918	  affected by entries in the DMI blacklist. Required by PNP
919	  BIOS code.
920
921config GART_IOMMU
922	bool "Old AMD GART IOMMU support"
923	select DMA_OPS
924	select IOMMU_HELPER
925	select SWIOTLB
926	depends on X86_64 && PCI && AMD_NB
927	help
928	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
929	  GART based hardware IOMMUs.
930
931	  The GART supports full DMA access for devices with 32-bit access
932	  limitations, on systems with more than 3 GB. This is usually needed
933	  for USB, sound, many IDE/SATA chipsets and some other devices.
934
935	  Newer systems typically have a modern AMD IOMMU, supported via
936	  the CONFIG_AMD_IOMMU=y config option.
937
938	  In normal configurations this driver is only active when needed:
939	  there's more than 3 GB of memory and the system contains a
940	  32-bit limited device.
941
942	  If unsure, say Y.
943
944config BOOT_VESA_SUPPORT
945	bool
946	help
947	  If true, at least one selected framebuffer driver can take advantage
948	  of VESA video modes set at an early boot stage via the vga= parameter.
949
950config MAXSMP
951	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
952	depends on X86_64 && SMP && DEBUG_KERNEL
953	select CPUMASK_OFFSTACK
954	help
955	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
956	  If unsure, say N.
957
958#
959# The maximum number of CPUs supported:
960#
961# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
962# and which can be configured interactively in the
963# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
964#
965# The ranges are different on 32-bit and 64-bit kernels, depending on
966# hardware capabilities and scalability features of the kernel.
967#
968# ( If MAXSMP is enabled we just use the highest possible value and disable
969#   interactive configuration. )
970#
971
972config NR_CPUS_RANGE_BEGIN
973	int
974	default NR_CPUS_RANGE_END if MAXSMP
975	default    1 if !SMP
976	default    2
977
978config NR_CPUS_RANGE_END
979	int
980	depends on X86_32
981	default   64 if  SMP &&  X86_BIGSMP
982	default    8 if  SMP && !X86_BIGSMP
983	default    1 if !SMP
984
985config NR_CPUS_RANGE_END
986	int
987	depends on X86_64
988	default 8192 if  SMP && CPUMASK_OFFSTACK
989	default  512 if  SMP && !CPUMASK_OFFSTACK
990	default    1 if !SMP
991
992config NR_CPUS_DEFAULT
993	int
994	depends on X86_32
995	default   32 if  X86_BIGSMP
996	default    8 if  SMP
997	default    1 if !SMP
998
999config NR_CPUS_DEFAULT
1000	int
1001	depends on X86_64
1002	default 8192 if  MAXSMP
1003	default   64 if  SMP
1004	default    1 if !SMP
1005
1006config NR_CPUS
1007	int "Maximum number of CPUs" if SMP && !MAXSMP
1008	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1009	default NR_CPUS_DEFAULT
1010	help
1011	  This allows you to specify the maximum number of CPUs which this
1012	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1013	  supported value is 8192, otherwise the maximum value is 512.  The
1014	  minimum value which makes sense is 2.
1015
1016	  This is purely to save memory: each supported CPU adds about 8KB
1017	  to the kernel image.
1018
1019config SCHED_CLUSTER
1020	bool "Cluster scheduler support"
1021	depends on SMP
1022	default y
1023	help
1024	  Cluster scheduler support improves the CPU scheduler's decision
1025	  making when dealing with machines that have clusters of CPUs.
1026	  Cluster usually means a couple of CPUs which are placed closely
1027	  by sharing mid-level caches, last-level cache tags or internal
1028	  busses.
1029
1030config SCHED_SMT
1031	def_bool y if SMP
1032
1033config SCHED_MC
1034	def_bool y
1035	prompt "Multi-core scheduler support"
1036	depends on SMP
1037	help
1038	  Multi-core scheduler support improves the CPU scheduler's decision
1039	  making when dealing with multi-core CPU chips at a cost of slightly
1040	  increased overhead in some places. If unsure say N here.
1041
1042config SCHED_MC_PRIO
1043	bool "CPU core priorities scheduler support"
1044	depends on SCHED_MC && CPU_SUP_INTEL
1045	select X86_INTEL_PSTATE
1046	select CPU_FREQ
1047	default y
1048	help
1049	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1050	  core ordering determined at manufacturing time, which allows
1051	  certain cores to reach higher turbo frequencies (when running
1052	  single threaded workloads) than others.
1053
1054	  Enabling this kernel feature teaches the scheduler about
1055	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1056	  scheduler's CPU selection logic accordingly, so that higher
1057	  overall system performance can be achieved.
1058
1059	  This feature will have no effect on CPUs without this feature.
1060
1061	  If unsure say Y here.
1062
1063config UP_LATE_INIT
1064	def_bool y
1065	depends on !SMP && X86_LOCAL_APIC
1066
1067config X86_UP_APIC
1068	bool "Local APIC support on uniprocessors" if !PCI_MSI
1069	default PCI_MSI
1070	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1071	help
1072	  A local APIC (Advanced Programmable Interrupt Controller) is an
1073	  integrated interrupt controller in the CPU. If you have a single-CPU
1074	  system which has a processor with a local APIC, you can say Y here to
1075	  enable and use it. If you say Y here even though your machine doesn't
1076	  have a local APIC, then the kernel will still run with no slowdown at
1077	  all. The local APIC supports CPU-generated self-interrupts (timer,
1078	  performance counters), and the NMI watchdog which detects hard
1079	  lockups.
1080
1081config X86_UP_IOAPIC
1082	bool "IO-APIC support on uniprocessors"
1083	depends on X86_UP_APIC
1084	help
1085	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1086	  SMP-capable replacement for PC-style interrupt controllers. Most
1087	  SMP systems and many recent uniprocessor systems have one.
1088
1089	  If you have a single-CPU system with an IO-APIC, you can say Y here
1090	  to use it. If you say Y here even though your machine doesn't have
1091	  an IO-APIC, then the kernel will still run with no slowdown at all.
1092
1093config X86_LOCAL_APIC
1094	def_bool y
1095	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1096	select IRQ_DOMAIN_HIERARCHY
1097	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1098
1099config X86_IO_APIC
1100	def_bool y
1101	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1102
1103config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1104	bool "Reroute for broken boot IRQs"
1105	depends on X86_IO_APIC
1106	help
1107	  This option enables a workaround that fixes a source of
1108	  spurious interrupts. This is recommended when threaded
1109	  interrupt handling is used on systems where the generation of
1110	  superfluous "boot interrupts" cannot be disabled.
1111
1112	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1113	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1114	  kernel does during interrupt handling). On chipsets where this
1115	  boot IRQ generation cannot be disabled, this workaround keeps
1116	  the original IRQ line masked so that only the equivalent "boot
1117	  IRQ" is delivered to the CPUs. The workaround also tells the
1118	  kernel to set up the IRQ handler on the boot IRQ line. In this
1119	  way only one interrupt is delivered to the kernel. Otherwise
1120	  the spurious second interrupt may cause the kernel to bring
1121	  down (vital) interrupt lines.
1122
1123	  Only affects "broken" chipsets. Interrupt sharing may be
1124	  increased on these systems.
1125
1126config X86_MCE
1127	bool "Machine Check / overheating reporting"
1128	select GENERIC_ALLOCATOR
1129	default y
1130	help
1131	  Machine Check support allows the processor to notify the
1132	  kernel if it detects a problem (e.g. overheating, data corruption).
1133	  The action the kernel takes depends on the severity of the problem,
1134	  ranging from warning messages to halting the machine.
1135
1136config X86_MCELOG_LEGACY
1137	bool "Support for deprecated /dev/mcelog character device"
1138	depends on X86_MCE
1139	help
1140	  Enable support for /dev/mcelog which is needed by the old mcelog
1141	  userspace logging daemon. Consider switching to the new generation
1142	  rasdaemon solution.
1143
1144config X86_MCE_INTEL
1145	def_bool y
1146	prompt "Intel MCE features"
1147	depends on X86_MCE && X86_LOCAL_APIC
1148	help
1149	  Additional support for intel specific MCE features such as
1150	  the thermal monitor.
1151
1152config X86_MCE_AMD
1153	def_bool y
1154	prompt "AMD MCE features"
1155	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1156	help
1157	  Additional support for AMD specific MCE features such as
1158	  the DRAM Error Threshold.
1159
1160config X86_ANCIENT_MCE
1161	bool "Support for old Pentium 5 / WinChip machine checks"
1162	depends on X86_32 && X86_MCE
1163	help
1164	  Include support for machine check handling on old Pentium 5 or WinChip
1165	  systems. These typically need to be enabled explicitly on the command
1166	  line.
1167
1168config X86_MCE_THRESHOLD
1169	depends on X86_MCE_AMD || X86_MCE_INTEL
1170	def_bool y
1171
1172config X86_MCE_INJECT
1173	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1174	tristate "Machine check injector support"
1175	help
1176	  Provide support for injecting machine checks for testing purposes.
1177	  If you don't know what a machine check is and you don't do kernel
1178	  QA it is safe to say n.
1179
1180source "arch/x86/events/Kconfig"
1181
1182config X86_LEGACY_VM86
1183	bool "Legacy VM86 support"
1184	depends on X86_32
1185	help
1186	  This option allows user programs to put the CPU into V8086
1187	  mode, which is an 80286-era approximation of 16-bit real mode.
1188
1189	  Some very old versions of X and/or vbetool require this option
1190	  for user mode setting.  Similarly, DOSEMU will use it if
1191	  available to accelerate real mode DOS programs.  However, any
1192	  recent version of DOSEMU, X, or vbetool should be fully
1193	  functional even without kernel VM86 support, as they will all
1194	  fall back to software emulation. Nevertheless, if you are using
1195	  a 16-bit DOS program where 16-bit performance matters, vm86
1196	  mode might be faster than emulation and you might want to
1197	  enable this option.
1198
1199	  Note that any app that works on a 64-bit kernel is unlikely to
1200	  need this option, as 64-bit kernels don't, and can't, support
1201	  V8086 mode. This option is also unrelated to 16-bit protected
1202	  mode and is not needed to run most 16-bit programs under Wine.
1203
1204	  Enabling this option increases the complexity of the kernel
1205	  and slows down exception handling a tiny bit.
1206
1207	  If unsure, say N here.
1208
1209config VM86
1210	bool
1211	default X86_LEGACY_VM86
1212
1213config X86_16BIT
1214	bool "Enable support for 16-bit segments" if EXPERT
1215	default y
1216	depends on MODIFY_LDT_SYSCALL
1217	help
1218	  This option is required by programs like Wine to run 16-bit
1219	  protected mode legacy code on x86 processors.  Disabling
1220	  this option saves about 300 bytes on i386, or around 6K text
1221	  plus 16K runtime memory on x86-64,
1222
1223config X86_ESPFIX32
1224	def_bool y
1225	depends on X86_16BIT && X86_32
1226
1227config X86_ESPFIX64
1228	def_bool y
1229	depends on X86_16BIT && X86_64
1230
1231config X86_VSYSCALL_EMULATION
1232	bool "Enable vsyscall emulation" if EXPERT
1233	default y
1234	depends on X86_64
1235	help
1236	  This enables emulation of the legacy vsyscall page.  Disabling
1237	  it is roughly equivalent to booting with vsyscall=none, except
1238	  that it will also disable the helpful warning if a program
1239	  tries to use a vsyscall.  With this option set to N, offending
1240	  programs will just segfault, citing addresses of the form
1241	  0xffffffffff600?00.
1242
1243	  This option is required by many programs built before 2013, and
1244	  care should be used even with newer programs if set to N.
1245
1246	  Disabling this option saves about 7K of kernel size and
1247	  possibly 4K of additional runtime pagetable memory.
1248
1249config X86_IOPL_IOPERM
1250	bool "IOPERM and IOPL Emulation"
1251	default y
1252	help
1253	  This enables the ioperm() and iopl() syscalls which are necessary
1254	  for legacy applications.
1255
1256	  Legacy IOPL support is an overbroad mechanism which allows user
1257	  space aside of accessing all 65536 I/O ports also to disable
1258	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1259	  capabilities and permission from potentially active security
1260	  modules.
1261
1262	  The emulation restricts the functionality of the syscall to
1263	  only allowing the full range I/O port access, but prevents the
1264	  ability to disable interrupts from user space which would be
1265	  granted if the hardware IOPL mechanism would be used.
1266
1267config TOSHIBA
1268	tristate "Toshiba Laptop support"
1269	depends on X86_32
1270	help
1271	  This adds a driver to safely access the System Management Mode of
1272	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1273	  not work on models with a Phoenix BIOS. The System Management Mode
1274	  is used to set the BIOS and power saving options on Toshiba portables.
1275
1276	  For information on utilities to make use of this driver see the
1277	  Toshiba Linux utilities web site at:
1278	  <http://www.buzzard.org.uk/toshiba/>.
1279
1280	  Say Y if you intend to run this kernel on a Toshiba portable.
1281	  Say N otherwise.
1282
1283config X86_REBOOTFIXUPS
1284	bool "Enable X86 board specific fixups for reboot"
1285	depends on X86_32
1286	help
1287	  This enables chipset and/or board specific fixups to be done
1288	  in order to get reboot to work correctly. This is only needed on
1289	  some combinations of hardware and BIOS. The symptom, for which
1290	  this config is intended, is when reboot ends with a stalled/hung
1291	  system.
1292
1293	  Currently, the only fixup is for the Geode machines using
1294	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1295
1296	  Say Y if you want to enable the fixup. Currently, it's safe to
1297	  enable this option even if you don't need it.
1298	  Say N otherwise.
1299
1300config MICROCODE
1301	bool "CPU microcode loading support"
1302	default y
1303	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1304	help
1305	  If you say Y here, you will be able to update the microcode on
1306	  Intel and AMD processors. The Intel support is for the IA32 family,
1307	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1308	  AMD support is for families 0x10 and later. You will obviously need
1309	  the actual microcode binary data itself which is not shipped with
1310	  the Linux kernel.
1311
1312	  The preferred method to load microcode from a detached initrd is described
1313	  in Documentation/x86/microcode.rst. For that you need to enable
1314	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1315	  initrd for microcode blobs.
1316
1317	  In addition, you can build the microcode into the kernel. For that you
1318	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1319	  config option.
1320
1321config MICROCODE_INTEL
1322	bool "Intel microcode loading support"
1323	depends on CPU_SUP_INTEL && MICROCODE
1324	default MICROCODE
1325	help
1326	  This options enables microcode patch loading support for Intel
1327	  processors.
1328
1329	  For the current Intel microcode data package go to
1330	  <https://downloadcenter.intel.com> and search for
1331	  'Linux Processor Microcode Data File'.
1332
1333config MICROCODE_AMD
1334	bool "AMD microcode loading support"
1335	depends on CPU_SUP_AMD && MICROCODE
1336	help
1337	  If you select this option, microcode patch loading support for AMD
1338	  processors will be enabled.
1339
1340config MICROCODE_LATE_LOADING
1341	bool "Late microcode loading (DANGEROUS)"
1342	default n
1343	depends on MICROCODE
1344	help
1345	  Loading microcode late, when the system is up and executing instructions
1346	  is a tricky business and should be avoided if possible. Just the sequence
1347	  of synchronizing all cores and SMT threads is one fragile dance which does
1348	  not guarantee that cores might not softlock after the loading. Therefore,
1349	  use this at your own risk. Late loading taints the kernel too.
1350
1351config X86_MSR
1352	tristate "/dev/cpu/*/msr - Model-specific register support"
1353	help
1354	  This device gives privileged processes access to the x86
1355	  Model-Specific Registers (MSRs).  It is a character device with
1356	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1357	  MSR accesses are directed to a specific CPU on multi-processor
1358	  systems.
1359
1360config X86_CPUID
1361	tristate "/dev/cpu/*/cpuid - CPU information support"
1362	help
1363	  This device gives processes access to the x86 CPUID instruction to
1364	  be executed on a specific processor.  It is a character device
1365	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1366	  /dev/cpu/31/cpuid.
1367
1368choice
1369	prompt "High Memory Support"
1370	default HIGHMEM4G
1371	depends on X86_32
1372
1373config NOHIGHMEM
1374	bool "off"
1375	help
1376	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1377	  However, the address space of 32-bit x86 processors is only 4
1378	  Gigabytes large. That means that, if you have a large amount of
1379	  physical memory, not all of it can be "permanently mapped" by the
1380	  kernel. The physical memory that's not permanently mapped is called
1381	  "high memory".
1382
1383	  If you are compiling a kernel which will never run on a machine with
1384	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1385	  choice and suitable for most users). This will result in a "3GB/1GB"
1386	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1387	  space and the remaining part of the 4GB virtual memory space is used
1388	  by the kernel to permanently map as much physical memory as
1389	  possible.
1390
1391	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1392	  answer "4GB" here.
1393
1394	  If more than 4 Gigabytes is used then answer "64GB" here. This
1395	  selection turns Intel PAE (Physical Address Extension) mode on.
1396	  PAE implements 3-level paging on IA32 processors. PAE is fully
1397	  supported by Linux, PAE mode is implemented on all recent Intel
1398	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1399	  then the kernel will not boot on CPUs that don't support PAE!
1400
1401	  The actual amount of total physical memory will either be
1402	  auto detected or can be forced by using a kernel command line option
1403	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1404	  your boot loader (lilo or loadlin) about how to pass options to the
1405	  kernel at boot time.)
1406
1407	  If unsure, say "off".
1408
1409config HIGHMEM4G
1410	bool "4GB"
1411	help
1412	  Select this if you have a 32-bit processor and between 1 and 4
1413	  gigabytes of physical RAM.
1414
1415config HIGHMEM64G
1416	bool "64GB"
1417	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1418	select X86_PAE
1419	help
1420	  Select this if you have a 32-bit processor and more than 4
1421	  gigabytes of physical RAM.
1422
1423endchoice
1424
1425choice
1426	prompt "Memory split" if EXPERT
1427	default VMSPLIT_3G
1428	depends on X86_32
1429	help
1430	  Select the desired split between kernel and user memory.
1431
1432	  If the address range available to the kernel is less than the
1433	  physical memory installed, the remaining memory will be available
1434	  as "high memory". Accessing high memory is a little more costly
1435	  than low memory, as it needs to be mapped into the kernel first.
1436	  Note that increasing the kernel address space limits the range
1437	  available to user programs, making the address space there
1438	  tighter.  Selecting anything other than the default 3G/1G split
1439	  will also likely make your kernel incompatible with binary-only
1440	  kernel modules.
1441
1442	  If you are not absolutely sure what you are doing, leave this
1443	  option alone!
1444
1445	config VMSPLIT_3G
1446		bool "3G/1G user/kernel split"
1447	config VMSPLIT_3G_OPT
1448		depends on !X86_PAE
1449		bool "3G/1G user/kernel split (for full 1G low memory)"
1450	config VMSPLIT_2G
1451		bool "2G/2G user/kernel split"
1452	config VMSPLIT_2G_OPT
1453		depends on !X86_PAE
1454		bool "2G/2G user/kernel split (for full 2G low memory)"
1455	config VMSPLIT_1G
1456		bool "1G/3G user/kernel split"
1457endchoice
1458
1459config PAGE_OFFSET
1460	hex
1461	default 0xB0000000 if VMSPLIT_3G_OPT
1462	default 0x80000000 if VMSPLIT_2G
1463	default 0x78000000 if VMSPLIT_2G_OPT
1464	default 0x40000000 if VMSPLIT_1G
1465	default 0xC0000000
1466	depends on X86_32
1467
1468config HIGHMEM
1469	def_bool y
1470	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1471
1472config X86_PAE
1473	bool "PAE (Physical Address Extension) Support"
1474	depends on X86_32 && !HIGHMEM4G
1475	select PHYS_ADDR_T_64BIT
1476	select SWIOTLB
1477	help
1478	  PAE is required for NX support, and furthermore enables
1479	  larger swapspace support for non-overcommit purposes. It
1480	  has the cost of more pagetable lookup overhead, and also
1481	  consumes more pagetable space per process.
1482
1483config X86_5LEVEL
1484	bool "Enable 5-level page tables support"
1485	default y
1486	select DYNAMIC_MEMORY_LAYOUT
1487	select SPARSEMEM_VMEMMAP
1488	depends on X86_64
1489	help
1490	  5-level paging enables access to larger address space:
1491	  upto 128 PiB of virtual address space and 4 PiB of
1492	  physical address space.
1493
1494	  It will be supported by future Intel CPUs.
1495
1496	  A kernel with the option enabled can be booted on machines that
1497	  support 4- or 5-level paging.
1498
1499	  See Documentation/x86/x86_64/5level-paging.rst for more
1500	  information.
1501
1502	  Say N if unsure.
1503
1504config X86_DIRECT_GBPAGES
1505	def_bool y
1506	depends on X86_64
1507	help
1508	  Certain kernel features effectively disable kernel
1509	  linear 1 GB mappings (even if the CPU otherwise
1510	  supports them), so don't confuse the user by printing
1511	  that we have them enabled.
1512
1513config X86_CPA_STATISTICS
1514	bool "Enable statistic for Change Page Attribute"
1515	depends on DEBUG_FS
1516	help
1517	  Expose statistics about the Change Page Attribute mechanism, which
1518	  helps to determine the effectiveness of preserving large and huge
1519	  page mappings when mapping protections are changed.
1520
1521config X86_MEM_ENCRYPT
1522	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1523	select DYNAMIC_PHYSICAL_MASK
1524	def_bool n
1525
1526config AMD_MEM_ENCRYPT
1527	bool "AMD Secure Memory Encryption (SME) support"
1528	depends on X86_64 && CPU_SUP_AMD
1529	select DMA_COHERENT_POOL
1530	select ARCH_USE_MEMREMAP_PROT
1531	select INSTRUCTION_DECODER
1532	select ARCH_HAS_CC_PLATFORM
1533	select X86_MEM_ENCRYPT
1534	help
1535	  Say yes to enable support for the encryption of system memory.
1536	  This requires an AMD processor that supports Secure Memory
1537	  Encryption (SME).
1538
1539config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1540	bool "Activate AMD Secure Memory Encryption (SME) by default"
1541	depends on AMD_MEM_ENCRYPT
1542	help
1543	  Say yes to have system memory encrypted by default if running on
1544	  an AMD processor that supports Secure Memory Encryption (SME).
1545
1546	  If set to Y, then the encryption of system memory can be
1547	  deactivated with the mem_encrypt=off command line option.
1548
1549	  If set to N, then the encryption of system memory can be
1550	  activated with the mem_encrypt=on command line option.
1551
1552# Common NUMA Features
1553config NUMA
1554	bool "NUMA Memory Allocation and Scheduler Support"
1555	depends on SMP
1556	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1557	default y if X86_BIGSMP
1558	select USE_PERCPU_NUMA_NODE_ID
1559	help
1560	  Enable NUMA (Non-Uniform Memory Access) support.
1561
1562	  The kernel will try to allocate memory used by a CPU on the
1563	  local memory controller of the CPU and add some more
1564	  NUMA awareness to the kernel.
1565
1566	  For 64-bit this is recommended if the system is Intel Core i7
1567	  (or later), AMD Opteron, or EM64T NUMA.
1568
1569	  For 32-bit this is only needed if you boot a 32-bit
1570	  kernel on a 64-bit NUMA platform.
1571
1572	  Otherwise, you should say N.
1573
1574config AMD_NUMA
1575	def_bool y
1576	prompt "Old style AMD Opteron NUMA detection"
1577	depends on X86_64 && NUMA && PCI
1578	help
1579	  Enable AMD NUMA node topology detection.  You should say Y here if
1580	  you have a multi processor AMD system. This uses an old method to
1581	  read the NUMA configuration directly from the builtin Northbridge
1582	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1583	  which also takes priority if both are compiled in.
1584
1585config X86_64_ACPI_NUMA
1586	def_bool y
1587	prompt "ACPI NUMA detection"
1588	depends on X86_64 && NUMA && ACPI && PCI
1589	select ACPI_NUMA
1590	help
1591	  Enable ACPI SRAT based node topology detection.
1592
1593config NUMA_EMU
1594	bool "NUMA emulation"
1595	depends on NUMA
1596	help
1597	  Enable NUMA emulation. A flat machine will be split
1598	  into virtual nodes when booted with "numa=fake=N", where N is the
1599	  number of nodes. This is only useful for debugging.
1600
1601config NODES_SHIFT
1602	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1603	range 1 10
1604	default "10" if MAXSMP
1605	default "6" if X86_64
1606	default "3"
1607	depends on NUMA
1608	help
1609	  Specify the maximum number of NUMA Nodes available on the target
1610	  system.  Increases memory reserved to accommodate various tables.
1611
1612config ARCH_FLATMEM_ENABLE
1613	def_bool y
1614	depends on X86_32 && !NUMA
1615
1616config ARCH_SPARSEMEM_ENABLE
1617	def_bool y
1618	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1619	select SPARSEMEM_STATIC if X86_32
1620	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1621
1622config ARCH_SPARSEMEM_DEFAULT
1623	def_bool X86_64 || (NUMA && X86_32)
1624
1625config ARCH_SELECT_MEMORY_MODEL
1626	def_bool y
1627	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1628
1629config ARCH_MEMORY_PROBE
1630	bool "Enable sysfs memory/probe interface"
1631	depends on MEMORY_HOTPLUG
1632	help
1633	  This option enables a sysfs memory/probe interface for testing.
1634	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1635	  If you are unsure how to answer this question, answer N.
1636
1637config ARCH_PROC_KCORE_TEXT
1638	def_bool y
1639	depends on X86_64 && PROC_KCORE
1640
1641config ILLEGAL_POINTER_VALUE
1642	hex
1643	default 0 if X86_32
1644	default 0xdead000000000000 if X86_64
1645
1646config X86_PMEM_LEGACY_DEVICE
1647	bool
1648
1649config X86_PMEM_LEGACY
1650	tristate "Support non-standard NVDIMMs and ADR protected memory"
1651	depends on PHYS_ADDR_T_64BIT
1652	depends on BLK_DEV
1653	select X86_PMEM_LEGACY_DEVICE
1654	select NUMA_KEEP_MEMINFO if NUMA
1655	select LIBNVDIMM
1656	help
1657	  Treat memory marked using the non-standard e820 type of 12 as used
1658	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1659	  The kernel will offer these regions to the 'pmem' driver so
1660	  they can be used for persistent storage.
1661
1662	  Say Y if unsure.
1663
1664config HIGHPTE
1665	bool "Allocate 3rd-level pagetables from highmem"
1666	depends on HIGHMEM
1667	help
1668	  The VM uses one page table entry for each page of physical memory.
1669	  For systems with a lot of RAM, this can be wasteful of precious
1670	  low memory.  Setting this option will put user-space page table
1671	  entries in high memory.
1672
1673config X86_CHECK_BIOS_CORRUPTION
1674	bool "Check for low memory corruption"
1675	help
1676	  Periodically check for memory corruption in low memory, which
1677	  is suspected to be caused by BIOS.  Even when enabled in the
1678	  configuration, it is disabled at runtime.  Enable it by
1679	  setting "memory_corruption_check=1" on the kernel command
1680	  line.  By default it scans the low 64k of memory every 60
1681	  seconds; see the memory_corruption_check_size and
1682	  memory_corruption_check_period parameters in
1683	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1684
1685	  When enabled with the default parameters, this option has
1686	  almost no overhead, as it reserves a relatively small amount
1687	  of memory and scans it infrequently.  It both detects corruption
1688	  and prevents it from affecting the running system.
1689
1690	  It is, however, intended as a diagnostic tool; if repeatable
1691	  BIOS-originated corruption always affects the same memory,
1692	  you can use memmap= to prevent the kernel from using that
1693	  memory.
1694
1695config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1696	bool "Set the default setting of memory_corruption_check"
1697	depends on X86_CHECK_BIOS_CORRUPTION
1698	default y
1699	help
1700	  Set whether the default state of memory_corruption_check is
1701	  on or off.
1702
1703config MATH_EMULATION
1704	bool
1705	depends on MODIFY_LDT_SYSCALL
1706	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1707	help
1708	  Linux can emulate a math coprocessor (used for floating point
1709	  operations) if you don't have one. 486DX and Pentium processors have
1710	  a math coprocessor built in, 486SX and 386 do not, unless you added
1711	  a 487DX or 387, respectively. (The messages during boot time can
1712	  give you some hints here ["man dmesg"].) Everyone needs either a
1713	  coprocessor or this emulation.
1714
1715	  If you don't have a math coprocessor, you need to say Y here; if you
1716	  say Y here even though you have a coprocessor, the coprocessor will
1717	  be used nevertheless. (This behavior can be changed with the kernel
1718	  command line option "no387", which comes handy if your coprocessor
1719	  is broken. Try "man bootparam" or see the documentation of your boot
1720	  loader (lilo or loadlin) about how to pass options to the kernel at
1721	  boot time.) This means that it is a good idea to say Y here if you
1722	  intend to use this kernel on different machines.
1723
1724	  More information about the internals of the Linux math coprocessor
1725	  emulation can be found in <file:arch/x86/math-emu/README>.
1726
1727	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1728	  kernel, it won't hurt.
1729
1730config MTRR
1731	def_bool y
1732	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1733	help
1734	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1735	  the Memory Type Range Registers (MTRRs) may be used to control
1736	  processor access to memory ranges. This is most useful if you have
1737	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1738	  allows bus write transfers to be combined into a larger transfer
1739	  before bursting over the PCI/AGP bus. This can increase performance
1740	  of image write operations 2.5 times or more. Saying Y here creates a
1741	  /proc/mtrr file which may be used to manipulate your processor's
1742	  MTRRs. Typically the X server should use this.
1743
1744	  This code has a reasonably generic interface so that similar
1745	  control registers on other processors can be easily supported
1746	  as well:
1747
1748	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1749	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1750	  these, the ARRs are used to emulate the MTRRs.
1751	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1752	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1753	  write-combining. All of these processors are supported by this code
1754	  and it makes sense to say Y here if you have one of them.
1755
1756	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1757	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1758	  can lead to all sorts of problems, so it's good to say Y here.
1759
1760	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1761	  just add about 9 KB to your kernel.
1762
1763	  See <file:Documentation/x86/mtrr.rst> for more information.
1764
1765config MTRR_SANITIZER
1766	def_bool y
1767	prompt "MTRR cleanup support"
1768	depends on MTRR
1769	help
1770	  Convert MTRR layout from continuous to discrete, so X drivers can
1771	  add writeback entries.
1772
1773	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1774	  The largest mtrr entry size for a continuous block can be set with
1775	  mtrr_chunk_size.
1776
1777	  If unsure, say Y.
1778
1779config MTRR_SANITIZER_ENABLE_DEFAULT
1780	int "MTRR cleanup enable value (0-1)"
1781	range 0 1
1782	default "0"
1783	depends on MTRR_SANITIZER
1784	help
1785	  Enable mtrr cleanup default value
1786
1787config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1788	int "MTRR cleanup spare reg num (0-7)"
1789	range 0 7
1790	default "1"
1791	depends on MTRR_SANITIZER
1792	help
1793	  mtrr cleanup spare entries default, it can be changed via
1794	  mtrr_spare_reg_nr=N on the kernel command line.
1795
1796config X86_PAT
1797	def_bool y
1798	prompt "x86 PAT support" if EXPERT
1799	depends on MTRR
1800	help
1801	  Use PAT attributes to setup page level cache control.
1802
1803	  PATs are the modern equivalents of MTRRs and are much more
1804	  flexible than MTRRs.
1805
1806	  Say N here if you see bootup problems (boot crash, boot hang,
1807	  spontaneous reboots) or a non-working video driver.
1808
1809	  If unsure, say Y.
1810
1811config ARCH_USES_PG_UNCACHED
1812	def_bool y
1813	depends on X86_PAT
1814
1815config ARCH_RANDOM
1816	def_bool y
1817	prompt "x86 architectural random number generator" if EXPERT
1818	help
1819	  Enable the x86 architectural RDRAND instruction
1820	  (Intel Bull Mountain technology) to generate random numbers.
1821	  If supported, this is a high bandwidth, cryptographically
1822	  secure hardware random number generator.
1823
1824config X86_UMIP
1825	def_bool y
1826	prompt "User Mode Instruction Prevention" if EXPERT
1827	help
1828	  User Mode Instruction Prevention (UMIP) is a security feature in
1829	  some x86 processors. If enabled, a general protection fault is
1830	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1831	  executed in user mode. These instructions unnecessarily expose
1832	  information about the hardware state.
1833
1834	  The vast majority of applications do not use these instructions.
1835	  For the very few that do, software emulation is provided in
1836	  specific cases in protected and virtual-8086 modes. Emulated
1837	  results are dummy.
1838
1839config CC_HAS_IBT
1840	# GCC >= 9 and binutils >= 2.29
1841	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1842	# Clang/LLVM >= 14
1843	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1844	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1845	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1846		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1847		  $(as-instr,endbr64)
1848
1849config X86_KERNEL_IBT
1850	prompt "Indirect Branch Tracking"
1851	bool
1852	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1853	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1854	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1855	select OBJTOOL
1856	help
1857	  Build the kernel with support for Indirect Branch Tracking, a
1858	  hardware support course-grain forward-edge Control Flow Integrity
1859	  protection. It enforces that all indirect calls must land on
1860	  an ENDBR instruction, as such, the compiler will instrument the
1861	  code with them to make this happen.
1862
1863	  In addition to building the kernel with IBT, seal all functions that
1864	  are not indirect call targets, avoiding them ever becoming one.
1865
1866	  This requires LTO like objtool runs and will slow down the build. It
1867	  does significantly reduce the number of ENDBR instructions in the
1868	  kernel image.
1869
1870config X86_INTEL_MEMORY_PROTECTION_KEYS
1871	prompt "Memory Protection Keys"
1872	def_bool y
1873	# Note: only available in 64-bit mode
1874	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1875	select ARCH_USES_HIGH_VMA_FLAGS
1876	select ARCH_HAS_PKEYS
1877	help
1878	  Memory Protection Keys provides a mechanism for enforcing
1879	  page-based protections, but without requiring modification of the
1880	  page tables when an application changes protection domains.
1881
1882	  For details, see Documentation/core-api/protection-keys.rst
1883
1884	  If unsure, say y.
1885
1886choice
1887	prompt "TSX enable mode"
1888	depends on CPU_SUP_INTEL
1889	default X86_INTEL_TSX_MODE_OFF
1890	help
1891	  Intel's TSX (Transactional Synchronization Extensions) feature
1892	  allows to optimize locking protocols through lock elision which
1893	  can lead to a noticeable performance boost.
1894
1895	  On the other hand it has been shown that TSX can be exploited
1896	  to form side channel attacks (e.g. TAA) and chances are there
1897	  will be more of those attacks discovered in the future.
1898
1899	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1900	  might override this decision by tsx=on the command line parameter.
1901	  Even with TSX enabled, the kernel will attempt to enable the best
1902	  possible TAA mitigation setting depending on the microcode available
1903	  for the particular machine.
1904
1905	  This option allows to set the default tsx mode between tsx=on, =off
1906	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1907	  details.
1908
1909	  Say off if not sure, auto if TSX is in use but it should be used on safe
1910	  platforms or on if TSX is in use and the security aspect of tsx is not
1911	  relevant.
1912
1913config X86_INTEL_TSX_MODE_OFF
1914	bool "off"
1915	help
1916	  TSX is disabled if possible - equals to tsx=off command line parameter.
1917
1918config X86_INTEL_TSX_MODE_ON
1919	bool "on"
1920	help
1921	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1922	  line parameter.
1923
1924config X86_INTEL_TSX_MODE_AUTO
1925	bool "auto"
1926	help
1927	  TSX is enabled on TSX capable HW that is believed to be safe against
1928	  side channel attacks- equals the tsx=auto command line parameter.
1929endchoice
1930
1931config X86_SGX
1932	bool "Software Guard eXtensions (SGX)"
1933	depends on X86_64 && CPU_SUP_INTEL
1934	depends on CRYPTO=y
1935	depends on CRYPTO_SHA256=y
1936	select SRCU
1937	select MMU_NOTIFIER
1938	select NUMA_KEEP_MEMINFO if NUMA
1939	select XARRAY_MULTI
1940	help
1941	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1942	  that can be used by applications to set aside private regions of code
1943	  and data, referred to as enclaves. An enclave's private memory can
1944	  only be accessed by code running within the enclave. Accesses from
1945	  outside the enclave, including other enclaves, are disallowed by
1946	  hardware.
1947
1948	  If unsure, say N.
1949
1950config EFI
1951	bool "EFI runtime service support"
1952	depends on ACPI
1953	select UCS2_STRING
1954	select EFI_RUNTIME_WRAPPERS
1955	select ARCH_USE_MEMREMAP_PROT
1956	help
1957	  This enables the kernel to use EFI runtime services that are
1958	  available (such as the EFI variable services).
1959
1960	  This option is only useful on systems that have EFI firmware.
1961	  In addition, you should use the latest ELILO loader available
1962	  at <http://elilo.sourceforge.net> in order to take advantage
1963	  of EFI runtime services. However, even with this option, the
1964	  resultant kernel should continue to boot on existing non-EFI
1965	  platforms.
1966
1967config EFI_STUB
1968	bool "EFI stub support"
1969	depends on EFI
1970	depends on $(cc-option,-mabi=ms) || X86_32
1971	select RELOCATABLE
1972	help
1973	  This kernel feature allows a bzImage to be loaded directly
1974	  by EFI firmware without the use of a bootloader.
1975
1976	  See Documentation/admin-guide/efi-stub.rst for more information.
1977
1978config EFI_MIXED
1979	bool "EFI mixed-mode support"
1980	depends on EFI_STUB && X86_64
1981	help
1982	  Enabling this feature allows a 64-bit kernel to be booted
1983	  on a 32-bit firmware, provided that your CPU supports 64-bit
1984	  mode.
1985
1986	  Note that it is not possible to boot a mixed-mode enabled
1987	  kernel via the EFI boot stub - a bootloader that supports
1988	  the EFI handover protocol must be used.
1989
1990	  If unsure, say N.
1991
1992source "kernel/Kconfig.hz"
1993
1994config KEXEC
1995	bool "kexec system call"
1996	select KEXEC_CORE
1997	help
1998	  kexec is a system call that implements the ability to shutdown your
1999	  current kernel, and to start another kernel.  It is like a reboot
2000	  but it is independent of the system firmware.   And like a reboot
2001	  you can start any kernel with it, not just Linux.
2002
2003	  The name comes from the similarity to the exec system call.
2004
2005	  It is an ongoing process to be certain the hardware in a machine
2006	  is properly shutdown, so do not be surprised if this code does not
2007	  initially work for you.  As of this writing the exact hardware
2008	  interface is strongly in flux, so no good recommendation can be
2009	  made.
2010
2011config KEXEC_FILE
2012	bool "kexec file based system call"
2013	select KEXEC_CORE
2014	select BUILD_BIN2C
2015	depends on X86_64
2016	depends on CRYPTO=y
2017	depends on CRYPTO_SHA256=y
2018	help
2019	  This is new version of kexec system call. This system call is
2020	  file based and takes file descriptors as system call argument
2021	  for kernel and initramfs as opposed to list of segments as
2022	  accepted by previous system call.
2023
2024config ARCH_HAS_KEXEC_PURGATORY
2025	def_bool KEXEC_FILE
2026
2027config KEXEC_SIG
2028	bool "Verify kernel signature during kexec_file_load() syscall"
2029	depends on KEXEC_FILE
2030	help
2031
2032	  This option makes the kexec_file_load() syscall check for a valid
2033	  signature of the kernel image.  The image can still be loaded without
2034	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2035	  there's a signature that we can check, then it must be valid.
2036
2037	  In addition to this option, you need to enable signature
2038	  verification for the corresponding kernel image type being
2039	  loaded in order for this to work.
2040
2041config KEXEC_SIG_FORCE
2042	bool "Require a valid signature in kexec_file_load() syscall"
2043	depends on KEXEC_SIG
2044	help
2045	  This option makes kernel signature verification mandatory for
2046	  the kexec_file_load() syscall.
2047
2048config KEXEC_BZIMAGE_VERIFY_SIG
2049	bool "Enable bzImage signature verification support"
2050	depends on KEXEC_SIG
2051	depends on SIGNED_PE_FILE_VERIFICATION
2052	select SYSTEM_TRUSTED_KEYRING
2053	help
2054	  Enable bzImage signature verification support.
2055
2056config CRASH_DUMP
2057	bool "kernel crash dumps"
2058	depends on X86_64 || (X86_32 && HIGHMEM)
2059	help
2060	  Generate crash dump after being started by kexec.
2061	  This should be normally only set in special crash dump kernels
2062	  which are loaded in the main kernel with kexec-tools into
2063	  a specially reserved region and then later executed after
2064	  a crash by kdump/kexec. The crash dump kernel must be compiled
2065	  to a memory address not used by the main kernel or BIOS using
2066	  PHYSICAL_START, or it must be built as a relocatable image
2067	  (CONFIG_RELOCATABLE=y).
2068	  For more details see Documentation/admin-guide/kdump/kdump.rst
2069
2070config KEXEC_JUMP
2071	bool "kexec jump"
2072	depends on KEXEC && HIBERNATION
2073	help
2074	  Jump between original kernel and kexeced kernel and invoke
2075	  code in physical address mode via KEXEC
2076
2077config PHYSICAL_START
2078	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2079	default "0x1000000"
2080	help
2081	  This gives the physical address where the kernel is loaded.
2082
2083	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2084	  bzImage will decompress itself to above physical address and
2085	  run from there. Otherwise, bzImage will run from the address where
2086	  it has been loaded by the boot loader and will ignore above physical
2087	  address.
2088
2089	  In normal kdump cases one does not have to set/change this option
2090	  as now bzImage can be compiled as a completely relocatable image
2091	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2092	  address. This option is mainly useful for the folks who don't want
2093	  to use a bzImage for capturing the crash dump and want to use a
2094	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2095	  to be specifically compiled to run from a specific memory area
2096	  (normally a reserved region) and this option comes handy.
2097
2098	  So if you are using bzImage for capturing the crash dump,
2099	  leave the value here unchanged to 0x1000000 and set
2100	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2101	  for capturing the crash dump change this value to start of
2102	  the reserved region.  In other words, it can be set based on
2103	  the "X" value as specified in the "crashkernel=YM@XM"
2104	  command line boot parameter passed to the panic-ed
2105	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2106	  for more details about crash dumps.
2107
2108	  Usage of bzImage for capturing the crash dump is recommended as
2109	  one does not have to build two kernels. Same kernel can be used
2110	  as production kernel and capture kernel. Above option should have
2111	  gone away after relocatable bzImage support is introduced. But it
2112	  is present because there are users out there who continue to use
2113	  vmlinux for dump capture. This option should go away down the
2114	  line.
2115
2116	  Don't change this unless you know what you are doing.
2117
2118config RELOCATABLE
2119	bool "Build a relocatable kernel"
2120	default y
2121	help
2122	  This builds a kernel image that retains relocation information
2123	  so it can be loaded someplace besides the default 1MB.
2124	  The relocations tend to make the kernel binary about 10% larger,
2125	  but are discarded at runtime.
2126
2127	  One use is for the kexec on panic case where the recovery kernel
2128	  must live at a different physical address than the primary
2129	  kernel.
2130
2131	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2132	  it has been loaded at and the compile time physical address
2133	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2134
2135config RANDOMIZE_BASE
2136	bool "Randomize the address of the kernel image (KASLR)"
2137	depends on RELOCATABLE
2138	default y
2139	help
2140	  In support of Kernel Address Space Layout Randomization (KASLR),
2141	  this randomizes the physical address at which the kernel image
2142	  is decompressed and the virtual address where the kernel
2143	  image is mapped, as a security feature that deters exploit
2144	  attempts relying on knowledge of the location of kernel
2145	  code internals.
2146
2147	  On 64-bit, the kernel physical and virtual addresses are
2148	  randomized separately. The physical address will be anywhere
2149	  between 16MB and the top of physical memory (up to 64TB). The
2150	  virtual address will be randomized from 16MB up to 1GB (9 bits
2151	  of entropy). Note that this also reduces the memory space
2152	  available to kernel modules from 1.5GB to 1GB.
2153
2154	  On 32-bit, the kernel physical and virtual addresses are
2155	  randomized together. They will be randomized from 16MB up to
2156	  512MB (8 bits of entropy).
2157
2158	  Entropy is generated using the RDRAND instruction if it is
2159	  supported. If RDTSC is supported, its value is mixed into
2160	  the entropy pool as well. If neither RDRAND nor RDTSC are
2161	  supported, then entropy is read from the i8254 timer. The
2162	  usable entropy is limited by the kernel being built using
2163	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2164	  minimum of 2MB. As a result, only 10 bits of entropy are
2165	  theoretically possible, but the implementations are further
2166	  limited due to memory layouts.
2167
2168	  If unsure, say Y.
2169
2170# Relocation on x86 needs some additional build support
2171config X86_NEED_RELOCS
2172	def_bool y
2173	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2174
2175config PHYSICAL_ALIGN
2176	hex "Alignment value to which kernel should be aligned"
2177	default "0x200000"
2178	range 0x2000 0x1000000 if X86_32
2179	range 0x200000 0x1000000 if X86_64
2180	help
2181	  This value puts the alignment restrictions on physical address
2182	  where kernel is loaded and run from. Kernel is compiled for an
2183	  address which meets above alignment restriction.
2184
2185	  If bootloader loads the kernel at a non-aligned address and
2186	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2187	  address aligned to above value and run from there.
2188
2189	  If bootloader loads the kernel at a non-aligned address and
2190	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2191	  load address and decompress itself to the address it has been
2192	  compiled for and run from there. The address for which kernel is
2193	  compiled already meets above alignment restrictions. Hence the
2194	  end result is that kernel runs from a physical address meeting
2195	  above alignment restrictions.
2196
2197	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2198	  this value must be a multiple of 0x200000.
2199
2200	  Don't change this unless you know what you are doing.
2201
2202config DYNAMIC_MEMORY_LAYOUT
2203	bool
2204	help
2205	  This option makes base addresses of vmalloc and vmemmap as well as
2206	  __PAGE_OFFSET movable during boot.
2207
2208config RANDOMIZE_MEMORY
2209	bool "Randomize the kernel memory sections"
2210	depends on X86_64
2211	depends on RANDOMIZE_BASE
2212	select DYNAMIC_MEMORY_LAYOUT
2213	default RANDOMIZE_BASE
2214	help
2215	  Randomizes the base virtual address of kernel memory sections
2216	  (physical memory mapping, vmalloc & vmemmap). This security feature
2217	  makes exploits relying on predictable memory locations less reliable.
2218
2219	  The order of allocations remains unchanged. Entropy is generated in
2220	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2221	  configuration have in average 30,000 different possible virtual
2222	  addresses for each memory section.
2223
2224	  If unsure, say Y.
2225
2226config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2227	hex "Physical memory mapping padding" if EXPERT
2228	depends on RANDOMIZE_MEMORY
2229	default "0xa" if MEMORY_HOTPLUG
2230	default "0x0"
2231	range 0x1 0x40 if MEMORY_HOTPLUG
2232	range 0x0 0x40
2233	help
2234	  Define the padding in terabytes added to the existing physical
2235	  memory size during kernel memory randomization. It is useful
2236	  for memory hotplug support but reduces the entropy available for
2237	  address randomization.
2238
2239	  If unsure, leave at the default value.
2240
2241config HOTPLUG_CPU
2242	def_bool y
2243	depends on SMP
2244
2245config BOOTPARAM_HOTPLUG_CPU0
2246	bool "Set default setting of cpu0_hotpluggable"
2247	depends on HOTPLUG_CPU
2248	help
2249	  Set whether default state of cpu0_hotpluggable is on or off.
2250
2251	  Say Y here to enable CPU0 hotplug by default. If this switch
2252	  is turned on, there is no need to give cpu0_hotplug kernel
2253	  parameter and the CPU0 hotplug feature is enabled by default.
2254
2255	  Please note: there are two known CPU0 dependencies if you want
2256	  to enable the CPU0 hotplug feature either by this switch or by
2257	  cpu0_hotplug kernel parameter.
2258
2259	  First, resume from hibernate or suspend always starts from CPU0.
2260	  So hibernate and suspend are prevented if CPU0 is offline.
2261
2262	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2263	  offline if any interrupt can not migrate out of CPU0. There may
2264	  be other CPU0 dependencies.
2265
2266	  Please make sure the dependencies are under your control before
2267	  you enable this feature.
2268
2269	  Say N if you don't want to enable CPU0 hotplug feature by default.
2270	  You still can enable the CPU0 hotplug feature at boot by kernel
2271	  parameter cpu0_hotplug.
2272
2273config DEBUG_HOTPLUG_CPU0
2274	def_bool n
2275	prompt "Debug CPU0 hotplug"
2276	depends on HOTPLUG_CPU
2277	help
2278	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2279	  soon as possible and boots up userspace with CPU0 offlined. User
2280	  can online CPU0 back after boot time.
2281
2282	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2283	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2284	  compilation or giving cpu0_hotplug kernel parameter at boot.
2285
2286	  If unsure, say N.
2287
2288config COMPAT_VDSO
2289	def_bool n
2290	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2291	depends on COMPAT_32
2292	help
2293	  Certain buggy versions of glibc will crash if they are
2294	  presented with a 32-bit vDSO that is not mapped at the address
2295	  indicated in its segment table.
2296
2297	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2298	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2299	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2300	  the only released version with the bug, but OpenSUSE 9
2301	  contains a buggy "glibc 2.3.2".
2302
2303	  The symptom of the bug is that everything crashes on startup, saying:
2304	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2305
2306	  Saying Y here changes the default value of the vdso32 boot
2307	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2308	  This works around the glibc bug but hurts performance.
2309
2310	  If unsure, say N: if you are compiling your own kernel, you
2311	  are unlikely to be using a buggy version of glibc.
2312
2313choice
2314	prompt "vsyscall table for legacy applications"
2315	depends on X86_64
2316	default LEGACY_VSYSCALL_XONLY
2317	help
2318	  Legacy user code that does not know how to find the vDSO expects
2319	  to be able to issue three syscalls by calling fixed addresses in
2320	  kernel space. Since this location is not randomized with ASLR,
2321	  it can be used to assist security vulnerability exploitation.
2322
2323	  This setting can be changed at boot time via the kernel command
2324	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2325	  is deprecated and can only be enabled using the kernel command
2326	  line.
2327
2328	  On a system with recent enough glibc (2.14 or newer) and no
2329	  static binaries, you can say None without a performance penalty
2330	  to improve security.
2331
2332	  If unsure, select "Emulate execution only".
2333
2334	config LEGACY_VSYSCALL_XONLY
2335		bool "Emulate execution only"
2336		help
2337		  The kernel traps and emulates calls into the fixed vsyscall
2338		  address mapping and does not allow reads.  This
2339		  configuration is recommended when userspace might use the
2340		  legacy vsyscall area but support for legacy binary
2341		  instrumentation of legacy code is not needed.  It mitigates
2342		  certain uses of the vsyscall area as an ASLR-bypassing
2343		  buffer.
2344
2345	config LEGACY_VSYSCALL_NONE
2346		bool "None"
2347		help
2348		  There will be no vsyscall mapping at all. This will
2349		  eliminate any risk of ASLR bypass due to the vsyscall
2350		  fixed address mapping. Attempts to use the vsyscalls
2351		  will be reported to dmesg, so that either old or
2352		  malicious userspace programs can be identified.
2353
2354endchoice
2355
2356config CMDLINE_BOOL
2357	bool "Built-in kernel command line"
2358	help
2359	  Allow for specifying boot arguments to the kernel at
2360	  build time.  On some systems (e.g. embedded ones), it is
2361	  necessary or convenient to provide some or all of the
2362	  kernel boot arguments with the kernel itself (that is,
2363	  to not rely on the boot loader to provide them.)
2364
2365	  To compile command line arguments into the kernel,
2366	  set this option to 'Y', then fill in the
2367	  boot arguments in CONFIG_CMDLINE.
2368
2369	  Systems with fully functional boot loaders (i.e. non-embedded)
2370	  should leave this option set to 'N'.
2371
2372config CMDLINE
2373	string "Built-in kernel command string"
2374	depends on CMDLINE_BOOL
2375	default ""
2376	help
2377	  Enter arguments here that should be compiled into the kernel
2378	  image and used at boot time.  If the boot loader provides a
2379	  command line at boot time, it is appended to this string to
2380	  form the full kernel command line, when the system boots.
2381
2382	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2383	  change this behavior.
2384
2385	  In most cases, the command line (whether built-in or provided
2386	  by the boot loader) should specify the device for the root
2387	  file system.
2388
2389config CMDLINE_OVERRIDE
2390	bool "Built-in command line overrides boot loader arguments"
2391	depends on CMDLINE_BOOL && CMDLINE != ""
2392	help
2393	  Set this option to 'Y' to have the kernel ignore the boot loader
2394	  command line, and use ONLY the built-in command line.
2395
2396	  This is used to work around broken boot loaders.  This should
2397	  be set to 'N' under normal conditions.
2398
2399config MODIFY_LDT_SYSCALL
2400	bool "Enable the LDT (local descriptor table)" if EXPERT
2401	default y
2402	help
2403	  Linux can allow user programs to install a per-process x86
2404	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2405	  call.  This is required to run 16-bit or segmented code such as
2406	  DOSEMU or some Wine programs.  It is also used by some very old
2407	  threading libraries.
2408
2409	  Enabling this feature adds a small amount of overhead to
2410	  context switches and increases the low-level kernel attack
2411	  surface.  Disabling it removes the modify_ldt(2) system call.
2412
2413	  Saying 'N' here may make sense for embedded or server kernels.
2414
2415config STRICT_SIGALTSTACK_SIZE
2416	bool "Enforce strict size checking for sigaltstack"
2417	depends on DYNAMIC_SIGFRAME
2418	help
2419	  For historical reasons MINSIGSTKSZ is a constant which became
2420	  already too small with AVX512 support. Add a mechanism to
2421	  enforce strict checking of the sigaltstack size against the
2422	  real size of the FPU frame. This option enables the check
2423	  by default. It can also be controlled via the kernel command
2424	  line option 'strict_sas_size' independent of this config
2425	  switch. Enabling it might break existing applications which
2426	  allocate a too small sigaltstack but 'work' because they
2427	  never get a signal delivered.
2428
2429	  Say 'N' unless you want to really enforce this check.
2430
2431source "kernel/livepatch/Kconfig"
2432
2433endmenu
2434
2435config CC_HAS_SLS
2436	def_bool $(cc-option,-mharden-sls=all)
2437
2438config CC_HAS_RETURN_THUNK
2439	def_bool $(cc-option,-mfunction-return=thunk-extern)
2440
2441menuconfig SPECULATION_MITIGATIONS
2442	bool "Mitigations for speculative execution vulnerabilities"
2443	default y
2444	help
2445	  Say Y here to enable options which enable mitigations for
2446	  speculative execution hardware vulnerabilities.
2447
2448	  If you say N, all mitigations will be disabled. You really
2449	  should know what you are doing to say so.
2450
2451if SPECULATION_MITIGATIONS
2452
2453config PAGE_TABLE_ISOLATION
2454	bool "Remove the kernel mapping in user mode"
2455	default y
2456	depends on (X86_64 || X86_PAE)
2457	help
2458	  This feature reduces the number of hardware side channels by
2459	  ensuring that the majority of kernel addresses are not mapped
2460	  into userspace.
2461
2462	  See Documentation/x86/pti.rst for more details.
2463
2464config RETPOLINE
2465	bool "Avoid speculative indirect branches in kernel"
2466	select OBJTOOL if HAVE_OBJTOOL
2467	default y
2468	help
2469	  Compile kernel with the retpoline compiler options to guard against
2470	  kernel-to-user data leaks by avoiding speculative indirect
2471	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2472	  support for full protection. The kernel may run slower.
2473
2474config RETHUNK
2475	bool "Enable return-thunks"
2476	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2477	select OBJTOOL if HAVE_OBJTOOL
2478	default y if X86_64
2479	help
2480	  Compile the kernel with the return-thunks compiler option to guard
2481	  against kernel-to-user data leaks by avoiding return speculation.
2482	  Requires a compiler with -mfunction-return=thunk-extern
2483	  support for full protection. The kernel may run slower.
2484
2485config CPU_UNRET_ENTRY
2486	bool "Enable UNRET on kernel entry"
2487	depends on CPU_SUP_AMD && RETHUNK && X86_64
2488	default y
2489	help
2490	  Compile the kernel with support for the retbleed=unret mitigation.
2491
2492config CPU_IBPB_ENTRY
2493	bool "Enable IBPB on kernel entry"
2494	depends on CPU_SUP_AMD && X86_64
2495	default y
2496	help
2497	  Compile the kernel with support for the retbleed=ibpb mitigation.
2498
2499config CPU_IBRS_ENTRY
2500	bool "Enable IBRS on kernel entry"
2501	depends on CPU_SUP_INTEL && X86_64
2502	default y
2503	help
2504	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2505	  This mitigates both spectre_v2 and retbleed at great cost to
2506	  performance.
2507
2508config SLS
2509	bool "Mitigate Straight-Line-Speculation"
2510	depends on CC_HAS_SLS && X86_64
2511	select OBJTOOL if HAVE_OBJTOOL
2512	default n
2513	help
2514	  Compile the kernel with straight-line-speculation options to guard
2515	  against straight line speculation. The kernel image might be slightly
2516	  larger.
2517
2518endif
2519
2520config ARCH_HAS_ADD_PAGES
2521	def_bool y
2522	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2523
2524config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2525	def_bool y
2526
2527menu "Power management and ACPI options"
2528
2529config ARCH_HIBERNATION_HEADER
2530	def_bool y
2531	depends on HIBERNATION
2532
2533source "kernel/power/Kconfig"
2534
2535source "drivers/acpi/Kconfig"
2536
2537config X86_APM_BOOT
2538	def_bool y
2539	depends on APM
2540
2541menuconfig APM
2542	tristate "APM (Advanced Power Management) BIOS support"
2543	depends on X86_32 && PM_SLEEP
2544	help
2545	  APM is a BIOS specification for saving power using several different
2546	  techniques. This is mostly useful for battery powered laptops with
2547	  APM compliant BIOSes. If you say Y here, the system time will be
2548	  reset after a RESUME operation, the /proc/apm device will provide
2549	  battery status information, and user-space programs will receive
2550	  notification of APM "events" (e.g. battery status change).
2551
2552	  If you select "Y" here, you can disable actual use of the APM
2553	  BIOS by passing the "apm=off" option to the kernel at boot time.
2554
2555	  Note that the APM support is almost completely disabled for
2556	  machines with more than one CPU.
2557
2558	  In order to use APM, you will need supporting software. For location
2559	  and more information, read <file:Documentation/power/apm-acpi.rst>
2560	  and the Battery Powered Linux mini-HOWTO, available from
2561	  <http://www.tldp.org/docs.html#howto>.
2562
2563	  This driver does not spin down disk drives (see the hdparm(8)
2564	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2565	  VESA-compliant "green" monitors.
2566
2567	  This driver does not support the TI 4000M TravelMate and the ACER
2568	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2569	  desktop machines also don't have compliant BIOSes, and this driver
2570	  may cause those machines to panic during the boot phase.
2571
2572	  Generally, if you don't have a battery in your machine, there isn't
2573	  much point in using this driver and you should say N. If you get
2574	  random kernel OOPSes or reboots that don't seem to be related to
2575	  anything, try disabling/enabling this option (or disabling/enabling
2576	  APM in your BIOS).
2577
2578	  Some other things you should try when experiencing seemingly random,
2579	  "weird" problems:
2580
2581	  1) make sure that you have enough swap space and that it is
2582	  enabled.
2583	  2) pass the "no-hlt" option to the kernel
2584	  3) switch on floating point emulation in the kernel and pass
2585	  the "no387" option to the kernel
2586	  4) pass the "floppy=nodma" option to the kernel
2587	  5) pass the "mem=4M" option to the kernel (thereby disabling
2588	  all but the first 4 MB of RAM)
2589	  6) make sure that the CPU is not over clocked.
2590	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2591	  8) disable the cache from your BIOS settings
2592	  9) install a fan for the video card or exchange video RAM
2593	  10) install a better fan for the CPU
2594	  11) exchange RAM chips
2595	  12) exchange the motherboard.
2596
2597	  To compile this driver as a module, choose M here: the
2598	  module will be called apm.
2599
2600if APM
2601
2602config APM_IGNORE_USER_SUSPEND
2603	bool "Ignore USER SUSPEND"
2604	help
2605	  This option will ignore USER SUSPEND requests. On machines with a
2606	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2607	  series notebooks, it is necessary to say Y because of a BIOS bug.
2608
2609config APM_DO_ENABLE
2610	bool "Enable PM at boot time"
2611	help
2612	  Enable APM features at boot time. From page 36 of the APM BIOS
2613	  specification: "When disabled, the APM BIOS does not automatically
2614	  power manage devices, enter the Standby State, enter the Suspend
2615	  State, or take power saving steps in response to CPU Idle calls."
2616	  This driver will make CPU Idle calls when Linux is idle (unless this
2617	  feature is turned off -- see "Do CPU IDLE calls", below). This
2618	  should always save battery power, but more complicated APM features
2619	  will be dependent on your BIOS implementation. You may need to turn
2620	  this option off if your computer hangs at boot time when using APM
2621	  support, or if it beeps continuously instead of suspending. Turn
2622	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2623	  T400CDT. This is off by default since most machines do fine without
2624	  this feature.
2625
2626config APM_CPU_IDLE
2627	depends on CPU_IDLE
2628	bool "Make CPU Idle calls when idle"
2629	help
2630	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2631	  On some machines, this can activate improved power savings, such as
2632	  a slowed CPU clock rate, when the machine is idle. These idle calls
2633	  are made after the idle loop has run for some length of time (e.g.,
2634	  333 mS). On some machines, this will cause a hang at boot time or
2635	  whenever the CPU becomes idle. (On machines with more than one CPU,
2636	  this option does nothing.)
2637
2638config APM_DISPLAY_BLANK
2639	bool "Enable console blanking using APM"
2640	help
2641	  Enable console blanking using the APM. Some laptops can use this to
2642	  turn off the LCD backlight when the screen blanker of the Linux
2643	  virtual console blanks the screen. Note that this is only used by
2644	  the virtual console screen blanker, and won't turn off the backlight
2645	  when using the X Window system. This also doesn't have anything to
2646	  do with your VESA-compliant power-saving monitor. Further, this
2647	  option doesn't work for all laptops -- it might not turn off your
2648	  backlight at all, or it might print a lot of errors to the console,
2649	  especially if you are using gpm.
2650
2651config APM_ALLOW_INTS
2652	bool "Allow interrupts during APM BIOS calls"
2653	help
2654	  Normally we disable external interrupts while we are making calls to
2655	  the APM BIOS as a measure to lessen the effects of a badly behaving
2656	  BIOS implementation.  The BIOS should reenable interrupts if it
2657	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2658	  many of the newer IBM Thinkpads.  If you experience hangs when you
2659	  suspend, try setting this to Y.  Otherwise, say N.
2660
2661endif # APM
2662
2663source "drivers/cpufreq/Kconfig"
2664
2665source "drivers/cpuidle/Kconfig"
2666
2667source "drivers/idle/Kconfig"
2668
2669endmenu
2670
2671menu "Bus options (PCI etc.)"
2672
2673choice
2674	prompt "PCI access mode"
2675	depends on X86_32 && PCI
2676	default PCI_GOANY
2677	help
2678	  On PCI systems, the BIOS can be used to detect the PCI devices and
2679	  determine their configuration. However, some old PCI motherboards
2680	  have BIOS bugs and may crash if this is done. Also, some embedded
2681	  PCI-based systems don't have any BIOS at all. Linux can also try to
2682	  detect the PCI hardware directly without using the BIOS.
2683
2684	  With this option, you can specify how Linux should detect the
2685	  PCI devices. If you choose "BIOS", the BIOS will be used,
2686	  if you choose "Direct", the BIOS won't be used, and if you
2687	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2688	  If you choose "Any", the kernel will try MMCONFIG, then the
2689	  direct access method and falls back to the BIOS if that doesn't
2690	  work. If unsure, go with the default, which is "Any".
2691
2692config PCI_GOBIOS
2693	bool "BIOS"
2694
2695config PCI_GOMMCONFIG
2696	bool "MMConfig"
2697
2698config PCI_GODIRECT
2699	bool "Direct"
2700
2701config PCI_GOOLPC
2702	bool "OLPC XO-1"
2703	depends on OLPC
2704
2705config PCI_GOANY
2706	bool "Any"
2707
2708endchoice
2709
2710config PCI_BIOS
2711	def_bool y
2712	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2713
2714# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2715config PCI_DIRECT
2716	def_bool y
2717	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2718
2719config PCI_MMCONFIG
2720	bool "Support mmconfig PCI config space access" if X86_64
2721	default y
2722	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2723	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2724
2725config PCI_OLPC
2726	def_bool y
2727	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2728
2729config PCI_XEN
2730	def_bool y
2731	depends on PCI && XEN
2732
2733config MMCONF_FAM10H
2734	def_bool y
2735	depends on X86_64 && PCI_MMCONFIG && ACPI
2736
2737config PCI_CNB20LE_QUIRK
2738	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2739	depends on PCI
2740	help
2741	  Read the PCI windows out of the CNB20LE host bridge. This allows
2742	  PCI hotplug to work on systems with the CNB20LE chipset which do
2743	  not have ACPI.
2744
2745	  There's no public spec for this chipset, and this functionality
2746	  is known to be incomplete.
2747
2748	  You should say N unless you know you need this.
2749
2750config ISA_BUS
2751	bool "ISA bus support on modern systems" if EXPERT
2752	help
2753	  Expose ISA bus device drivers and options available for selection and
2754	  configuration. Enable this option if your target machine has an ISA
2755	  bus. ISA is an older system, displaced by PCI and newer bus
2756	  architectures -- if your target machine is modern, it probably does
2757	  not have an ISA bus.
2758
2759	  If unsure, say N.
2760
2761# x86_64 have no ISA slots, but can have ISA-style DMA.
2762config ISA_DMA_API
2763	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2764	default y
2765	help
2766	  Enables ISA-style DMA support for devices requiring such controllers.
2767	  If unsure, say Y.
2768
2769if X86_32
2770
2771config ISA
2772	bool "ISA support"
2773	help
2774	  Find out whether you have ISA slots on your motherboard.  ISA is the
2775	  name of a bus system, i.e. the way the CPU talks to the other stuff
2776	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2777	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2778	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2779
2780config SCx200
2781	tristate "NatSemi SCx200 support"
2782	help
2783	  This provides basic support for National Semiconductor's
2784	  (now AMD's) Geode processors.  The driver probes for the
2785	  PCI-IDs of several on-chip devices, so its a good dependency
2786	  for other scx200_* drivers.
2787
2788	  If compiled as a module, the driver is named scx200.
2789
2790config SCx200HR_TIMER
2791	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2792	depends on SCx200
2793	default y
2794	help
2795	  This driver provides a clocksource built upon the on-chip
2796	  27MHz high-resolution timer.  Its also a workaround for
2797	  NSC Geode SC-1100's buggy TSC, which loses time when the
2798	  processor goes idle (as is done by the scheduler).  The
2799	  other workaround is idle=poll boot option.
2800
2801config OLPC
2802	bool "One Laptop Per Child support"
2803	depends on !X86_PAE
2804	select GPIOLIB
2805	select OF
2806	select OF_PROMTREE
2807	select IRQ_DOMAIN
2808	select OLPC_EC
2809	help
2810	  Add support for detecting the unique features of the OLPC
2811	  XO hardware.
2812
2813config OLPC_XO1_PM
2814	bool "OLPC XO-1 Power Management"
2815	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2816	help
2817	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2818
2819config OLPC_XO1_RTC
2820	bool "OLPC XO-1 Real Time Clock"
2821	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2822	help
2823	  Add support for the XO-1 real time clock, which can be used as a
2824	  programmable wakeup source.
2825
2826config OLPC_XO1_SCI
2827	bool "OLPC XO-1 SCI extras"
2828	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2829	depends on INPUT=y
2830	select POWER_SUPPLY
2831	help
2832	  Add support for SCI-based features of the OLPC XO-1 laptop:
2833	   - EC-driven system wakeups
2834	   - Power button
2835	   - Ebook switch
2836	   - Lid switch
2837	   - AC adapter status updates
2838	   - Battery status updates
2839
2840config OLPC_XO15_SCI
2841	bool "OLPC XO-1.5 SCI extras"
2842	depends on OLPC && ACPI
2843	select POWER_SUPPLY
2844	help
2845	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2846	   - EC-driven system wakeups
2847	   - AC adapter status updates
2848	   - Battery status updates
2849
2850config ALIX
2851	bool "PCEngines ALIX System Support (LED setup)"
2852	select GPIOLIB
2853	help
2854	  This option enables system support for the PCEngines ALIX.
2855	  At present this just sets up LEDs for GPIO control on
2856	  ALIX2/3/6 boards.  However, other system specific setup should
2857	  get added here.
2858
2859	  Note: You must still enable the drivers for GPIO and LED support
2860	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2861
2862	  Note: You have to set alix.force=1 for boards with Award BIOS.
2863
2864config NET5501
2865	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2866	select GPIOLIB
2867	help
2868	  This option enables system support for the Soekris Engineering net5501.
2869
2870config GEOS
2871	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2872	select GPIOLIB
2873	depends on DMI
2874	help
2875	  This option enables system support for the Traverse Technologies GEOS.
2876
2877config TS5500
2878	bool "Technologic Systems TS-5500 platform support"
2879	depends on MELAN
2880	select CHECK_SIGNATURE
2881	select NEW_LEDS
2882	select LEDS_CLASS
2883	help
2884	  This option enables system support for the Technologic Systems TS-5500.
2885
2886endif # X86_32
2887
2888config AMD_NB
2889	def_bool y
2890	depends on CPU_SUP_AMD && PCI
2891
2892endmenu
2893
2894menu "Binary Emulations"
2895
2896config IA32_EMULATION
2897	bool "IA32 Emulation"
2898	depends on X86_64
2899	select ARCH_WANT_OLD_COMPAT_IPC
2900	select BINFMT_ELF
2901	select COMPAT_OLD_SIGACTION
2902	help
2903	  Include code to run legacy 32-bit programs under a
2904	  64-bit kernel. You should likely turn this on, unless you're
2905	  100% sure that you don't have any 32-bit programs left.
2906
2907config X86_X32_ABI
2908	bool "x32 ABI for 64-bit mode"
2909	depends on X86_64
2910	# llvm-objcopy does not convert x86_64 .note.gnu.property or
2911	# compressed debug sections to x86_x32 properly:
2912	# https://github.com/ClangBuiltLinux/linux/issues/514
2913	# https://github.com/ClangBuiltLinux/linux/issues/1141
2914	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
2915	help
2916	  Include code to run binaries for the x32 native 32-bit ABI
2917	  for 64-bit processors.  An x32 process gets access to the
2918	  full 64-bit register file and wide data path while leaving
2919	  pointers at 32 bits for smaller memory footprint.
2920
2921config COMPAT_32
2922	def_bool y
2923	depends on IA32_EMULATION || X86_32
2924	select HAVE_UID16
2925	select OLD_SIGSUSPEND3
2926
2927config COMPAT
2928	def_bool y
2929	depends on IA32_EMULATION || X86_X32_ABI
2930
2931config COMPAT_FOR_U64_ALIGNMENT
2932	def_bool y
2933	depends on COMPAT
2934
2935endmenu
2936
2937config HAVE_ATOMIC_IOMAP
2938	def_bool y
2939	depends on X86_32
2940
2941source "arch/x86/kvm/Kconfig"
2942
2943source "arch/x86/Kconfig.assembler"
2944