xref: /openbmc/linux/arch/x86/Kconfig (revision dc023681)
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_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
65	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 || (X86_32 && HIGHMEM)
66	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
67	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
68	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
69	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
70	select ARCH_HAS_CACHE_LINE_SIZE
71	select ARCH_HAS_DEBUG_VIRTUAL
72	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
73	select ARCH_HAS_DEVMEM_IS_ALLOWED
74	select ARCH_HAS_EARLY_DEBUG		if KGDB
75	select ARCH_HAS_ELF_RANDOMIZE
76	select ARCH_HAS_FAST_MULTIPLIER
77	select ARCH_HAS_FILTER_PGPROT
78	select ARCH_HAS_FORTIFY_SOURCE
79	select ARCH_HAS_GCOV_PROFILE_ALL
80	select ARCH_HAS_KCOV			if X86_64 && STACK_VALIDATION
81	select ARCH_HAS_MEM_ENCRYPT
82	select ARCH_HAS_MEMBARRIER_SYNC_CORE
83	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
84	select ARCH_HAS_PMEM_API		if X86_64
85	select ARCH_HAS_PTE_DEVMAP		if X86_64
86	select ARCH_HAS_PTE_SPECIAL
87	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
88	select ARCH_HAS_COPY_MC			if X86_64
89	select ARCH_HAS_SET_MEMORY
90	select ARCH_HAS_SET_DIRECT_MAP
91	select ARCH_HAS_STRICT_KERNEL_RWX
92	select ARCH_HAS_STRICT_MODULE_RWX
93	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
94	select ARCH_HAS_SYSCALL_WRAPPER
95	select ARCH_HAS_UBSAN_SANITIZE_ALL
96	select ARCH_HAS_DEBUG_WX
97	select ARCH_HAS_ZONE_DMA_SET if EXPERT
98	select ARCH_HAVE_NMI_SAFE_CMPXCHG
99	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
100	select ARCH_MIGHT_HAVE_PC_PARPORT
101	select ARCH_MIGHT_HAVE_PC_SERIO
102	select ARCH_STACKWALK
103	select ARCH_SUPPORTS_ACPI
104	select ARCH_SUPPORTS_ATOMIC_RMW
105	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
106	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
107	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
108	select ARCH_SUPPORTS_LTO_CLANG
109	select ARCH_SUPPORTS_LTO_CLANG_THIN
110	select ARCH_USE_BUILTIN_BSWAP
111	select ARCH_USE_MEMTEST
112	select ARCH_USE_QUEUED_RWLOCKS
113	select ARCH_USE_QUEUED_SPINLOCKS
114	select ARCH_USE_SYM_ANNOTATIONS
115	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
116	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
117	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
118	select ARCH_WANTS_NO_INSTR
119	select ARCH_WANT_HUGE_PMD_SHARE
120	select ARCH_WANT_LD_ORPHAN_WARN
121	select ARCH_WANTS_THP_SWAP		if X86_64
122	select ARCH_HAS_PARANOID_L1D_FLUSH
123	select BUILDTIME_TABLE_SORT
124	select CLKEVT_I8253
125	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
126	select CLOCKSOURCE_WATCHDOG
127	select DCACHE_WORD_ACCESS
128	select EDAC_ATOMIC_SCRUB
129	select EDAC_SUPPORT
130	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
131	select GENERIC_CLOCKEVENTS_MIN_ADJUST
132	select GENERIC_CMOS_UPDATE
133	select GENERIC_CPU_AUTOPROBE
134	select GENERIC_CPU_VULNERABILITIES
135	select GENERIC_EARLY_IOREMAP
136	select GENERIC_ENTRY
137	select GENERIC_FIND_FIRST_BIT
138	select GENERIC_IOMAP
139	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
140	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
141	select GENERIC_IRQ_MIGRATION		if SMP
142	select GENERIC_IRQ_PROBE
143	select GENERIC_IRQ_RESERVATION_MODE
144	select GENERIC_IRQ_SHOW
145	select GENERIC_PENDING_IRQ		if SMP
146	select GENERIC_PTDUMP
147	select GENERIC_SMP_IDLE_THREAD
148	select GENERIC_TIME_VSYSCALL
149	select GENERIC_GETTIMEOFDAY
150	select GENERIC_VDSO_TIME_NS
151	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
152	select HARDIRQS_SW_RESEND
153	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
154	select HAVE_ACPI_APEI			if ACPI
155	select HAVE_ACPI_APEI_NMI		if ACPI
156	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
157	select HAVE_ARCH_AUDITSYSCALL
158	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
159	select HAVE_ARCH_JUMP_LABEL
160	select HAVE_ARCH_JUMP_LABEL_RELATIVE
161	select HAVE_ARCH_KASAN			if X86_64
162	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
163	select HAVE_ARCH_KFENCE
164	select HAVE_ARCH_KGDB
165	select HAVE_ARCH_MMAP_RND_BITS		if MMU
166	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
167	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
168	select HAVE_ARCH_PREL32_RELOCATIONS
169	select HAVE_ARCH_SECCOMP_FILTER
170	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
171	select HAVE_ARCH_STACKLEAK
172	select HAVE_ARCH_TRACEHOOK
173	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
174	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
175	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
176	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
177	select HAVE_ARCH_VMAP_STACK		if X86_64
178	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
179	select HAVE_ARCH_WITHIN_STACK_FRAMES
180	select HAVE_ASM_MODVERSIONS
181	select HAVE_CMPXCHG_DOUBLE
182	select HAVE_CMPXCHG_LOCAL
183	select HAVE_CONTEXT_TRACKING		if X86_64
184	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
185	select HAVE_C_RECORDMCOUNT
186	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
187	select HAVE_DEBUG_KMEMLEAK
188	select HAVE_DMA_CONTIGUOUS
189	select HAVE_DYNAMIC_FTRACE
190	select HAVE_DYNAMIC_FTRACE_WITH_REGS
191	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
192	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
193	select HAVE_EBPF_JIT
194	select HAVE_EFFICIENT_UNALIGNED_ACCESS
195	select HAVE_EISA
196	select HAVE_EXIT_THREAD
197	select HAVE_FAST_GUP
198	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
199	select HAVE_FTRACE_MCOUNT_RECORD
200	select HAVE_FUNCTION_GRAPH_TRACER
201	select HAVE_FUNCTION_TRACER
202	select HAVE_GCC_PLUGINS
203	select HAVE_HW_BREAKPOINT
204	select HAVE_IOREMAP_PROT
205	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
206	select HAVE_IRQ_TIME_ACCOUNTING
207	select HAVE_KERNEL_BZIP2
208	select HAVE_KERNEL_GZIP
209	select HAVE_KERNEL_LZ4
210	select HAVE_KERNEL_LZMA
211	select HAVE_KERNEL_LZO
212	select HAVE_KERNEL_XZ
213	select HAVE_KERNEL_ZSTD
214	select HAVE_KPROBES
215	select HAVE_KPROBES_ON_FTRACE
216	select HAVE_FUNCTION_ERROR_INJECTION
217	select HAVE_KRETPROBES
218	select HAVE_KVM
219	select HAVE_LIVEPATCH			if X86_64
220	select HAVE_MIXED_BREAKPOINTS_REGS
221	select HAVE_MOD_ARCH_SPECIFIC
222	select HAVE_MOVE_PMD
223	select HAVE_MOVE_PUD
224	select HAVE_NMI
225	select HAVE_OPTPROBES
226	select HAVE_PCSPKR_PLATFORM
227	select HAVE_PERF_EVENTS
228	select HAVE_PERF_EVENTS_NMI
229	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
230	select HAVE_PCI
231	select HAVE_PERF_REGS
232	select HAVE_PERF_USER_STACK_DUMP
233	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
234	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
235	select HAVE_REGS_AND_STACK_ACCESS_API
236	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
237	select HAVE_FUNCTION_ARG_ACCESS_API
238	select HAVE_SOFTIRQ_ON_OWN_STACK
239	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
240	select HAVE_STACK_VALIDATION		if X86_64
241	select HAVE_STATIC_CALL
242	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
243	select HAVE_PREEMPT_DYNAMIC
244	select HAVE_RSEQ
245	select HAVE_SYSCALL_TRACEPOINTS
246	select HAVE_UNSTABLE_SCHED_CLOCK
247	select HAVE_USER_RETURN_NOTIFIER
248	select HAVE_GENERIC_VDSO
249	select HOTPLUG_SMT			if SMP
250	select IRQ_FORCED_THREADING
251	select NEED_SG_DMA_LENGTH
252	select PCI_DOMAINS			if PCI
253	select PCI_LOCKLESS_CONFIG		if PCI
254	select PERF_EVENTS
255	select RTC_LIB
256	select RTC_MC146818_LIB
257	select SPARSE_IRQ
258	select SRCU
259	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
260	select SYSCTL_EXCEPTION_TRACE
261	select THREAD_INFO_IN_TASK
262	select TRACE_IRQFLAGS_SUPPORT
263	select USER_STACKTRACE_SUPPORT
264	select VIRT_TO_BUS
265	select HAVE_ARCH_KCSAN			if X86_64
266	select X86_FEATURE_NAMES		if PROC_FS
267	select PROC_PID_ARCH_STATUS		if PROC_FS
268	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
269
270config INSTRUCTION_DECODER
271	def_bool y
272	depends on KPROBES || PERF_EVENTS || UPROBES
273
274config OUTPUT_FORMAT
275	string
276	default "elf32-i386" if X86_32
277	default "elf64-x86-64" if X86_64
278
279config LOCKDEP_SUPPORT
280	def_bool y
281
282config STACKTRACE_SUPPORT
283	def_bool y
284
285config MMU
286	def_bool y
287
288config ARCH_MMAP_RND_BITS_MIN
289	default 28 if 64BIT
290	default 8
291
292config ARCH_MMAP_RND_BITS_MAX
293	default 32 if 64BIT
294	default 16
295
296config ARCH_MMAP_RND_COMPAT_BITS_MIN
297	default 8
298
299config ARCH_MMAP_RND_COMPAT_BITS_MAX
300	default 16
301
302config SBUS
303	bool
304
305config GENERIC_ISA_DMA
306	def_bool y
307	depends on ISA_DMA_API
308
309config GENERIC_BUG
310	def_bool y
311	depends on BUG
312	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
313
314config GENERIC_BUG_RELATIVE_POINTERS
315	bool
316
317config ARCH_MAY_HAVE_PC_FDC
318	def_bool y
319	depends on ISA_DMA_API
320
321config GENERIC_CALIBRATE_DELAY
322	def_bool y
323
324config ARCH_HAS_CPU_RELAX
325	def_bool y
326
327config ARCH_HAS_FILTER_PGPROT
328	def_bool y
329
330config HAVE_SETUP_PER_CPU_AREA
331	def_bool y
332
333config NEED_PER_CPU_EMBED_FIRST_CHUNK
334	def_bool y
335
336config NEED_PER_CPU_PAGE_FIRST_CHUNK
337	def_bool y
338
339config ARCH_HIBERNATION_POSSIBLE
340	def_bool y
341
342config ARCH_NR_GPIO
343	int
344	default 1024 if X86_64
345	default 512
346
347config ARCH_SUSPEND_POSSIBLE
348	def_bool y
349
350config ARCH_WANT_GENERAL_HUGETLB
351	def_bool y
352
353config AUDIT_ARCH
354	def_bool y if X86_64
355
356config KASAN_SHADOW_OFFSET
357	hex
358	depends on KASAN
359	default 0xdffffc0000000000
360
361config HAVE_INTEL_TXT
362	def_bool y
363	depends on INTEL_IOMMU && ACPI
364
365config X86_32_SMP
366	def_bool y
367	depends on X86_32 && SMP
368
369config X86_64_SMP
370	def_bool y
371	depends on X86_64 && SMP
372
373config ARCH_SUPPORTS_UPROBES
374	def_bool y
375
376config FIX_EARLYCON_MEM
377	def_bool y
378
379config DYNAMIC_PHYSICAL_MASK
380	bool
381
382config PGTABLE_LEVELS
383	int
384	default 5 if X86_5LEVEL
385	default 4 if X86_64
386	default 3 if X86_PAE
387	default 2
388
389config CC_HAS_SANE_STACKPROTECTOR
390	bool
391	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
392	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
393	help
394	   We have to make sure stack protector is unconditionally disabled if
395	   the compiler produces broken code or if it does not let us control
396	   the segment on 32-bit kernels.
397
398menu "Processor type and features"
399
400config SMP
401	bool "Symmetric multi-processing support"
402	help
403	  This enables support for systems with more than one CPU. If you have
404	  a system with only one CPU, say N. If you have a system with more
405	  than one CPU, say Y.
406
407	  If you say N here, the kernel will run on uni- and multiprocessor
408	  machines, but will use only one CPU of a multiprocessor machine. If
409	  you say Y here, the kernel will run on many, but not all,
410	  uniprocessor machines. On a uniprocessor machine, the kernel
411	  will run faster if you say N here.
412
413	  Note that if you say Y here and choose architecture "586" or
414	  "Pentium" under "Processor family", the kernel will not work on 486
415	  architectures. Similarly, multiprocessor kernels for the "PPro"
416	  architecture may not work on all Pentium based boards.
417
418	  People using multiprocessor machines who say Y here should also say
419	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
420	  Management" code will be disabled if you say Y here.
421
422	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
423	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
424	  <http://www.tldp.org/docs.html#howto>.
425
426	  If you don't know what to do here, say N.
427
428config X86_FEATURE_NAMES
429	bool "Processor feature human-readable names" if EMBEDDED
430	default y
431	help
432	  This option compiles in a table of x86 feature bits and corresponding
433	  names.  This is required to support /proc/cpuinfo and a few kernel
434	  messages.  You can disable this to save space, at the expense of
435	  making those few kernel messages show numeric feature bits instead.
436
437	  If in doubt, say Y.
438
439config X86_X2APIC
440	bool "Support x2apic"
441	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
442	help
443	  This enables x2apic support on CPUs that have this feature.
444
445	  This allows 32-bit apic IDs (so it can support very large systems),
446	  and accesses the local apic via MSRs not via mmio.
447
448	  If you don't know what to do here, say N.
449
450config X86_MPPARSE
451	bool "Enable MPS table" if ACPI
452	default y
453	depends on X86_LOCAL_APIC
454	help
455	  For old smp systems that do not have proper acpi support. Newer systems
456	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
457
458config GOLDFISH
459	def_bool y
460	depends on X86_GOLDFISH
461
462config RETPOLINE
463	bool "Avoid speculative indirect branches in kernel"
464	default y
465	help
466	  Compile kernel with the retpoline compiler options to guard against
467	  kernel-to-user data leaks by avoiding speculative indirect
468	  branches. Requires a compiler with -mindirect-branch=thunk-extern
469	  support for full protection. The kernel may run slower.
470
471config X86_CPU_RESCTRL
472	bool "x86 CPU resource control support"
473	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
474	select KERNFS
475	select PROC_CPU_RESCTRL		if PROC_FS
476	help
477	  Enable x86 CPU resource control support.
478
479	  Provide support for the allocation and monitoring of system resources
480	  usage by the CPU.
481
482	  Intel calls this Intel Resource Director Technology
483	  (Intel(R) RDT). More information about RDT can be found in the
484	  Intel x86 Architecture Software Developer Manual.
485
486	  AMD calls this AMD Platform Quality of Service (AMD QoS).
487	  More information about AMD QoS can be found in the AMD64 Technology
488	  Platform Quality of Service Extensions manual.
489
490	  Say N if unsure.
491
492if X86_32
493config X86_BIGSMP
494	bool "Support for big SMP systems with more than 8 CPUs"
495	depends on SMP
496	help
497	  This option is needed for the systems that have more than 8 CPUs.
498
499config X86_EXTENDED_PLATFORM
500	bool "Support for extended (non-PC) x86 platforms"
501	default y
502	help
503	  If you disable this option then the kernel will only support
504	  standard PC platforms. (which covers the vast majority of
505	  systems out there.)
506
507	  If you enable this option then you'll be able to select support
508	  for the following (non-PC) 32 bit x86 platforms:
509		Goldfish (Android emulator)
510		AMD Elan
511		RDC R-321x SoC
512		SGI 320/540 (Visual Workstation)
513		STA2X11-based (e.g. Northville)
514		Moorestown MID devices
515
516	  If you have one of these systems, or if you want to build a
517	  generic distribution kernel, say Y here - otherwise say N.
518endif
519
520if X86_64
521config X86_EXTENDED_PLATFORM
522	bool "Support for extended (non-PC) x86 platforms"
523	default y
524	help
525	  If you disable this option then the kernel will only support
526	  standard PC platforms. (which covers the vast majority of
527	  systems out there.)
528
529	  If you enable this option then you'll be able to select support
530	  for the following (non-PC) 64 bit x86 platforms:
531		Numascale NumaChip
532		ScaleMP vSMP
533		SGI Ultraviolet
534
535	  If you have one of these systems, or if you want to build a
536	  generic distribution kernel, say Y here - otherwise say N.
537endif
538# This is an alphabetically sorted list of 64 bit extended platforms
539# Please maintain the alphabetic order if and when there are additions
540config X86_NUMACHIP
541	bool "Numascale NumaChip"
542	depends on X86_64
543	depends on X86_EXTENDED_PLATFORM
544	depends on NUMA
545	depends on SMP
546	depends on X86_X2APIC
547	depends on PCI_MMCONFIG
548	help
549	  Adds support for Numascale NumaChip large-SMP systems. Needed to
550	  enable more than ~168 cores.
551	  If you don't have one of these, you should say N here.
552
553config X86_VSMP
554	bool "ScaleMP vSMP"
555	select HYPERVISOR_GUEST
556	select PARAVIRT
557	depends on X86_64 && PCI
558	depends on X86_EXTENDED_PLATFORM
559	depends on SMP
560	help
561	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
562	  supposed to run on these EM64T-based machines.  Only choose this option
563	  if you have one of these machines.
564
565config X86_UV
566	bool "SGI Ultraviolet"
567	depends on X86_64
568	depends on X86_EXTENDED_PLATFORM
569	depends on NUMA
570	depends on EFI
571	depends on KEXEC_CORE
572	depends on X86_X2APIC
573	depends on PCI
574	help
575	  This option is needed in order to support SGI Ultraviolet systems.
576	  If you don't have one of these, you should say N here.
577
578# Following is an alphabetically sorted list of 32 bit extended platforms
579# Please maintain the alphabetic order if and when there are additions
580
581config X86_GOLDFISH
582	bool "Goldfish (Virtual Platform)"
583	depends on X86_EXTENDED_PLATFORM
584	help
585	 Enable support for the Goldfish virtual platform used primarily
586	 for Android development. Unless you are building for the Android
587	 Goldfish emulator say N here.
588
589config X86_INTEL_CE
590	bool "CE4100 TV platform"
591	depends on PCI
592	depends on PCI_GODIRECT
593	depends on X86_IO_APIC
594	depends on X86_32
595	depends on X86_EXTENDED_PLATFORM
596	select X86_REBOOTFIXUPS
597	select OF
598	select OF_EARLY_FLATTREE
599	help
600	  Select for the Intel CE media processor (CE4100) SOC.
601	  This option compiles in support for the CE4100 SOC for settop
602	  boxes and media devices.
603
604config X86_INTEL_MID
605	bool "Intel MID platform support"
606	depends on X86_EXTENDED_PLATFORM
607	depends on X86_PLATFORM_DEVICES
608	depends on PCI
609	depends on X86_64 || (PCI_GOANY && X86_32)
610	depends on X86_IO_APIC
611	select I2C
612	select DW_APB_TIMER
613	select APB_TIMER
614	select INTEL_SCU_PCI
615	select MFD_INTEL_MSIC
616	help
617	  Select to build a kernel capable of supporting Intel MID (Mobile
618	  Internet Device) platform systems which do not have the PCI legacy
619	  interfaces. If you are building for a PC class system say N here.
620
621	  Intel MID platforms are based on an Intel processor and chipset which
622	  consume less power than most of the x86 derivatives.
623
624config X86_INTEL_QUARK
625	bool "Intel Quark platform support"
626	depends on X86_32
627	depends on X86_EXTENDED_PLATFORM
628	depends on X86_PLATFORM_DEVICES
629	depends on X86_TSC
630	depends on PCI
631	depends on PCI_GOANY
632	depends on X86_IO_APIC
633	select IOSF_MBI
634	select INTEL_IMR
635	select COMMON_CLK
636	help
637	  Select to include support for Quark X1000 SoC.
638	  Say Y here if you have a Quark based system such as the Arduino
639	  compatible Intel Galileo.
640
641config X86_INTEL_LPSS
642	bool "Intel Low Power Subsystem Support"
643	depends on X86 && ACPI && PCI
644	select COMMON_CLK
645	select PINCTRL
646	select IOSF_MBI
647	help
648	  Select to build support for Intel Low Power Subsystem such as
649	  found on Intel Lynxpoint PCH. Selecting this option enables
650	  things like clock tree (common clock framework) and pincontrol
651	  which are needed by the LPSS peripheral drivers.
652
653config X86_AMD_PLATFORM_DEVICE
654	bool "AMD ACPI2Platform devices support"
655	depends on ACPI
656	select COMMON_CLK
657	select PINCTRL
658	help
659	  Select to interpret AMD specific ACPI device to platform device
660	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
661	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
662	  implemented under PINCTRL subsystem.
663
664config IOSF_MBI
665	tristate "Intel SoC IOSF Sideband support for SoC platforms"
666	depends on PCI
667	help
668	  This option enables sideband register access support for Intel SoC
669	  platforms. On these platforms the IOSF sideband is used in lieu of
670	  MSR's for some register accesses, mostly but not limited to thermal
671	  and power. Drivers may query the availability of this device to
672	  determine if they need the sideband in order to work on these
673	  platforms. The sideband is available on the following SoC products.
674	  This list is not meant to be exclusive.
675	   - BayTrail
676	   - Braswell
677	   - Quark
678
679	  You should say Y if you are running a kernel on one of these SoC's.
680
681config IOSF_MBI_DEBUG
682	bool "Enable IOSF sideband access through debugfs"
683	depends on IOSF_MBI && DEBUG_FS
684	help
685	  Select this option to expose the IOSF sideband access registers (MCR,
686	  MDR, MCRX) through debugfs to write and read register information from
687	  different units on the SoC. This is most useful for obtaining device
688	  state information for debug and analysis. As this is a general access
689	  mechanism, users of this option would have specific knowledge of the
690	  device they want to access.
691
692	  If you don't require the option or are in doubt, say N.
693
694config X86_RDC321X
695	bool "RDC R-321x SoC"
696	depends on X86_32
697	depends on X86_EXTENDED_PLATFORM
698	select M486
699	select X86_REBOOTFIXUPS
700	help
701	  This option is needed for RDC R-321x system-on-chip, also known
702	  as R-8610-(G).
703	  If you don't have one of these chips, you should say N here.
704
705config X86_32_NON_STANDARD
706	bool "Support non-standard 32-bit SMP architectures"
707	depends on X86_32 && SMP
708	depends on X86_EXTENDED_PLATFORM
709	help
710	  This option compiles in the bigsmp and STA2X11 default
711	  subarchitectures.  It is intended for a generic binary
712	  kernel. If you select them all, kernel will probe it one by
713	  one and will fallback to default.
714
715# Alphabetically sorted list of Non standard 32 bit platforms
716
717config X86_SUPPORTS_MEMORY_FAILURE
718	def_bool y
719	# MCE code calls memory_failure():
720	depends on X86_MCE
721	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
722	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
723	depends on X86_64 || !SPARSEMEM
724	select ARCH_SUPPORTS_MEMORY_FAILURE
725
726config STA2X11
727	bool "STA2X11 Companion Chip Support"
728	depends on X86_32_NON_STANDARD && PCI
729	select SWIOTLB
730	select MFD_STA2X11
731	select GPIOLIB
732	help
733	  This adds support for boards based on the STA2X11 IO-Hub,
734	  a.k.a. "ConneXt". The chip is used in place of the standard
735	  PC chipset, so all "standard" peripherals are missing. If this
736	  option is selected the kernel will still be able to boot on
737	  standard PC machines.
738
739config X86_32_IRIS
740	tristate "Eurobraille/Iris poweroff module"
741	depends on X86_32
742	help
743	  The Iris machines from EuroBraille do not have APM or ACPI support
744	  to shut themselves down properly.  A special I/O sequence is
745	  needed to do so, which is what this module does at
746	  kernel shutdown.
747
748	  This is only for Iris machines from EuroBraille.
749
750	  If unused, say N.
751
752config SCHED_OMIT_FRAME_POINTER
753	def_bool y
754	prompt "Single-depth WCHAN output"
755	depends on X86
756	help
757	  Calculate simpler /proc/<PID>/wchan values. If this option
758	  is disabled then wchan values will recurse back to the
759	  caller function. This provides more accurate wchan values,
760	  at the expense of slightly more scheduling overhead.
761
762	  If in doubt, say "Y".
763
764menuconfig HYPERVISOR_GUEST
765	bool "Linux guest support"
766	help
767	  Say Y here to enable options for running Linux under various hyper-
768	  visors. This option enables basic hypervisor detection and platform
769	  setup.
770
771	  If you say N, all options in this submenu will be skipped and
772	  disabled, and Linux guest support won't be built in.
773
774if HYPERVISOR_GUEST
775
776config PARAVIRT
777	bool "Enable paravirtualization code"
778	depends on HAVE_STATIC_CALL
779	help
780	  This changes the kernel so it can modify itself when it is run
781	  under a hypervisor, potentially improving performance significantly
782	  over full virtualization.  However, when run without a hypervisor
783	  the kernel is theoretically slower and slightly larger.
784
785config PARAVIRT_XXL
786	bool
787
788config PARAVIRT_DEBUG
789	bool "paravirt-ops debugging"
790	depends on PARAVIRT && DEBUG_KERNEL
791	help
792	  Enable to debug paravirt_ops internals.  Specifically, BUG if
793	  a paravirt_op is missing when it is called.
794
795config PARAVIRT_SPINLOCKS
796	bool "Paravirtualization layer for spinlocks"
797	depends on PARAVIRT && SMP
798	help
799	  Paravirtualized spinlocks allow a pvops backend to replace the
800	  spinlock implementation with something virtualization-friendly
801	  (for example, block the virtual CPU rather than spinning).
802
803	  It has a minimal impact on native kernels and gives a nice performance
804	  benefit on paravirtualized KVM / Xen kernels.
805
806	  If you are unsure how to answer this question, answer Y.
807
808config X86_HV_CALLBACK_VECTOR
809	def_bool n
810
811source "arch/x86/xen/Kconfig"
812
813config KVM_GUEST
814	bool "KVM Guest support (including kvmclock)"
815	depends on PARAVIRT
816	select PARAVIRT_CLOCK
817	select ARCH_CPUIDLE_HALTPOLL
818	select X86_HV_CALLBACK_VECTOR
819	default y
820	help
821	  This option enables various optimizations for running under the KVM
822	  hypervisor. It includes a paravirtualized clock, so that instead
823	  of relying on a PIT (or probably other) emulation by the
824	  underlying device model, the host provides the guest with
825	  timing infrastructure such as time of day, and system time
826
827config ARCH_CPUIDLE_HALTPOLL
828	def_bool n
829	prompt "Disable host haltpoll when loading haltpoll driver"
830	help
831	  If virtualized under KVM, disable host haltpoll.
832
833config PVH
834	bool "Support for running PVH guests"
835	help
836	  This option enables the PVH entry point for guest virtual machines
837	  as specified in the x86/HVM direct boot ABI.
838
839config PARAVIRT_TIME_ACCOUNTING
840	bool "Paravirtual steal time accounting"
841	depends on PARAVIRT
842	help
843	  Select this option to enable fine granularity task steal time
844	  accounting. Time spent executing other tasks in parallel with
845	  the current vCPU is discounted from the vCPU power. To account for
846	  that, there can be a small performance impact.
847
848	  If in doubt, say N here.
849
850config PARAVIRT_CLOCK
851	bool
852
853config JAILHOUSE_GUEST
854	bool "Jailhouse non-root cell support"
855	depends on X86_64 && PCI
856	select X86_PM_TIMER
857	help
858	  This option allows to run Linux as guest in a Jailhouse non-root
859	  cell. You can leave this option disabled if you only want to start
860	  Jailhouse and run Linux afterwards in the root cell.
861
862config ACRN_GUEST
863	bool "ACRN Guest support"
864	depends on X86_64
865	select X86_HV_CALLBACK_VECTOR
866	help
867	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
868	  a flexible, lightweight reference open-source hypervisor, built with
869	  real-time and safety-criticality in mind. It is built for embedded
870	  IOT with small footprint and real-time features. More details can be
871	  found in https://projectacrn.org/.
872
873endif #HYPERVISOR_GUEST
874
875source "arch/x86/Kconfig.cpu"
876
877config HPET_TIMER
878	def_bool X86_64
879	prompt "HPET Timer Support" if X86_32
880	help
881	  Use the IA-PC HPET (High Precision Event Timer) to manage
882	  time in preference to the PIT and RTC, if a HPET is
883	  present.
884	  HPET is the next generation timer replacing legacy 8254s.
885	  The HPET provides a stable time base on SMP
886	  systems, unlike the TSC, but it is more expensive to access,
887	  as it is off-chip.  The interface used is documented
888	  in the HPET spec, revision 1.
889
890	  You can safely choose Y here.  However, HPET will only be
891	  activated if the platform and the BIOS support this feature.
892	  Otherwise the 8254 will be used for timing services.
893
894	  Choose N to continue using the legacy 8254 timer.
895
896config HPET_EMULATE_RTC
897	def_bool y
898	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
899
900# Mark as expert because too many people got it wrong.
901# The code disables itself when not needed.
902config DMI
903	default y
904	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
905	bool "Enable DMI scanning" if EXPERT
906	help
907	  Enabled scanning of DMI to identify machine quirks. Say Y
908	  here unless you have verified that your setup is not
909	  affected by entries in the DMI blacklist. Required by PNP
910	  BIOS code.
911
912config GART_IOMMU
913	bool "Old AMD GART IOMMU support"
914	select DMA_OPS
915	select IOMMU_HELPER
916	select SWIOTLB
917	depends on X86_64 && PCI && AMD_NB
918	help
919	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
920	  GART based hardware IOMMUs.
921
922	  The GART supports full DMA access for devices with 32-bit access
923	  limitations, on systems with more than 3 GB. This is usually needed
924	  for USB, sound, many IDE/SATA chipsets and some other devices.
925
926	  Newer systems typically have a modern AMD IOMMU, supported via
927	  the CONFIG_AMD_IOMMU=y config option.
928
929	  In normal configurations this driver is only active when needed:
930	  there's more than 3 GB of memory and the system contains a
931	  32-bit limited device.
932
933	  If unsure, say Y.
934
935config MAXSMP
936	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
937	depends on X86_64 && SMP && DEBUG_KERNEL
938	select CPUMASK_OFFSTACK
939	help
940	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
941	  If unsure, say N.
942
943#
944# The maximum number of CPUs supported:
945#
946# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
947# and which can be configured interactively in the
948# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
949#
950# The ranges are different on 32-bit and 64-bit kernels, depending on
951# hardware capabilities and scalability features of the kernel.
952#
953# ( If MAXSMP is enabled we just use the highest possible value and disable
954#   interactive configuration. )
955#
956
957config NR_CPUS_RANGE_BEGIN
958	int
959	default NR_CPUS_RANGE_END if MAXSMP
960	default    1 if !SMP
961	default    2
962
963config NR_CPUS_RANGE_END
964	int
965	depends on X86_32
966	default   64 if  SMP &&  X86_BIGSMP
967	default    8 if  SMP && !X86_BIGSMP
968	default    1 if !SMP
969
970config NR_CPUS_RANGE_END
971	int
972	depends on X86_64
973	default 8192 if  SMP && CPUMASK_OFFSTACK
974	default  512 if  SMP && !CPUMASK_OFFSTACK
975	default    1 if !SMP
976
977config NR_CPUS_DEFAULT
978	int
979	depends on X86_32
980	default   32 if  X86_BIGSMP
981	default    8 if  SMP
982	default    1 if !SMP
983
984config NR_CPUS_DEFAULT
985	int
986	depends on X86_64
987	default 8192 if  MAXSMP
988	default   64 if  SMP
989	default    1 if !SMP
990
991config NR_CPUS
992	int "Maximum number of CPUs" if SMP && !MAXSMP
993	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
994	default NR_CPUS_DEFAULT
995	help
996	  This allows you to specify the maximum number of CPUs which this
997	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
998	  supported value is 8192, otherwise the maximum value is 512.  The
999	  minimum value which makes sense is 2.
1000
1001	  This is purely to save memory: each supported CPU adds about 8KB
1002	  to the kernel image.
1003
1004config SCHED_SMT
1005	def_bool y if SMP
1006
1007config SCHED_MC
1008	def_bool y
1009	prompt "Multi-core scheduler support"
1010	depends on SMP
1011	help
1012	  Multi-core scheduler support improves the CPU scheduler's decision
1013	  making when dealing with multi-core CPU chips at a cost of slightly
1014	  increased overhead in some places. If unsure say N here.
1015
1016config SCHED_MC_PRIO
1017	bool "CPU core priorities scheduler support"
1018	depends on SCHED_MC && CPU_SUP_INTEL
1019	select X86_INTEL_PSTATE
1020	select CPU_FREQ
1021	default y
1022	help
1023	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1024	  core ordering determined at manufacturing time, which allows
1025	  certain cores to reach higher turbo frequencies (when running
1026	  single threaded workloads) than others.
1027
1028	  Enabling this kernel feature teaches the scheduler about
1029	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1030	  scheduler's CPU selection logic accordingly, so that higher
1031	  overall system performance can be achieved.
1032
1033	  This feature will have no effect on CPUs without this feature.
1034
1035	  If unsure say Y here.
1036
1037config UP_LATE_INIT
1038	def_bool y
1039	depends on !SMP && X86_LOCAL_APIC
1040
1041config X86_UP_APIC
1042	bool "Local APIC support on uniprocessors" if !PCI_MSI
1043	default PCI_MSI
1044	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1045	help
1046	  A local APIC (Advanced Programmable Interrupt Controller) is an
1047	  integrated interrupt controller in the CPU. If you have a single-CPU
1048	  system which has a processor with a local APIC, you can say Y here to
1049	  enable and use it. If you say Y here even though your machine doesn't
1050	  have a local APIC, then the kernel will still run with no slowdown at
1051	  all. The local APIC supports CPU-generated self-interrupts (timer,
1052	  performance counters), and the NMI watchdog which detects hard
1053	  lockups.
1054
1055config X86_UP_IOAPIC
1056	bool "IO-APIC support on uniprocessors"
1057	depends on X86_UP_APIC
1058	help
1059	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1060	  SMP-capable replacement for PC-style interrupt controllers. Most
1061	  SMP systems and many recent uniprocessor systems have one.
1062
1063	  If you have a single-CPU system with an IO-APIC, you can say Y here
1064	  to use it. If you say Y here even though your machine doesn't have
1065	  an IO-APIC, then the kernel will still run with no slowdown at all.
1066
1067config X86_LOCAL_APIC
1068	def_bool y
1069	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1070	select IRQ_DOMAIN_HIERARCHY
1071	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1072
1073config X86_IO_APIC
1074	def_bool y
1075	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1076
1077config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1078	bool "Reroute for broken boot IRQs"
1079	depends on X86_IO_APIC
1080	help
1081	  This option enables a workaround that fixes a source of
1082	  spurious interrupts. This is recommended when threaded
1083	  interrupt handling is used on systems where the generation of
1084	  superfluous "boot interrupts" cannot be disabled.
1085
1086	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1087	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1088	  kernel does during interrupt handling). On chipsets where this
1089	  boot IRQ generation cannot be disabled, this workaround keeps
1090	  the original IRQ line masked so that only the equivalent "boot
1091	  IRQ" is delivered to the CPUs. The workaround also tells the
1092	  kernel to set up the IRQ handler on the boot IRQ line. In this
1093	  way only one interrupt is delivered to the kernel. Otherwise
1094	  the spurious second interrupt may cause the kernel to bring
1095	  down (vital) interrupt lines.
1096
1097	  Only affects "broken" chipsets. Interrupt sharing may be
1098	  increased on these systems.
1099
1100config X86_MCE
1101	bool "Machine Check / overheating reporting"
1102	select GENERIC_ALLOCATOR
1103	default y
1104	help
1105	  Machine Check support allows the processor to notify the
1106	  kernel if it detects a problem (e.g. overheating, data corruption).
1107	  The action the kernel takes depends on the severity of the problem,
1108	  ranging from warning messages to halting the machine.
1109
1110config X86_MCELOG_LEGACY
1111	bool "Support for deprecated /dev/mcelog character device"
1112	depends on X86_MCE
1113	help
1114	  Enable support for /dev/mcelog which is needed by the old mcelog
1115	  userspace logging daemon. Consider switching to the new generation
1116	  rasdaemon solution.
1117
1118config X86_MCE_INTEL
1119	def_bool y
1120	prompt "Intel MCE features"
1121	depends on X86_MCE && X86_LOCAL_APIC
1122	help
1123	   Additional support for intel specific MCE features such as
1124	   the thermal monitor.
1125
1126config X86_MCE_AMD
1127	def_bool y
1128	prompt "AMD MCE features"
1129	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1130	help
1131	   Additional support for AMD specific MCE features such as
1132	   the DRAM Error Threshold.
1133
1134config X86_ANCIENT_MCE
1135	bool "Support for old Pentium 5 / WinChip machine checks"
1136	depends on X86_32 && X86_MCE
1137	help
1138	  Include support for machine check handling on old Pentium 5 or WinChip
1139	  systems. These typically need to be enabled explicitly on the command
1140	  line.
1141
1142config X86_MCE_THRESHOLD
1143	depends on X86_MCE_AMD || X86_MCE_INTEL
1144	def_bool y
1145
1146config X86_MCE_INJECT
1147	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1148	tristate "Machine check injector support"
1149	help
1150	  Provide support for injecting machine checks for testing purposes.
1151	  If you don't know what a machine check is and you don't do kernel
1152	  QA it is safe to say n.
1153
1154source "arch/x86/events/Kconfig"
1155
1156config X86_LEGACY_VM86
1157	bool "Legacy VM86 support"
1158	depends on X86_32
1159	help
1160	  This option allows user programs to put the CPU into V8086
1161	  mode, which is an 80286-era approximation of 16-bit real mode.
1162
1163	  Some very old versions of X and/or vbetool require this option
1164	  for user mode setting.  Similarly, DOSEMU will use it if
1165	  available to accelerate real mode DOS programs.  However, any
1166	  recent version of DOSEMU, X, or vbetool should be fully
1167	  functional even without kernel VM86 support, as they will all
1168	  fall back to software emulation. Nevertheless, if you are using
1169	  a 16-bit DOS program where 16-bit performance matters, vm86
1170	  mode might be faster than emulation and you might want to
1171	  enable this option.
1172
1173	  Note that any app that works on a 64-bit kernel is unlikely to
1174	  need this option, as 64-bit kernels don't, and can't, support
1175	  V8086 mode. This option is also unrelated to 16-bit protected
1176	  mode and is not needed to run most 16-bit programs under Wine.
1177
1178	  Enabling this option increases the complexity of the kernel
1179	  and slows down exception handling a tiny bit.
1180
1181	  If unsure, say N here.
1182
1183config VM86
1184	bool
1185	default X86_LEGACY_VM86
1186
1187config X86_16BIT
1188	bool "Enable support for 16-bit segments" if EXPERT
1189	default y
1190	depends on MODIFY_LDT_SYSCALL
1191	help
1192	  This option is required by programs like Wine to run 16-bit
1193	  protected mode legacy code on x86 processors.  Disabling
1194	  this option saves about 300 bytes on i386, or around 6K text
1195	  plus 16K runtime memory on x86-64,
1196
1197config X86_ESPFIX32
1198	def_bool y
1199	depends on X86_16BIT && X86_32
1200
1201config X86_ESPFIX64
1202	def_bool y
1203	depends on X86_16BIT && X86_64
1204
1205config X86_VSYSCALL_EMULATION
1206	bool "Enable vsyscall emulation" if EXPERT
1207	default y
1208	depends on X86_64
1209	help
1210	 This enables emulation of the legacy vsyscall page.  Disabling
1211	 it is roughly equivalent to booting with vsyscall=none, except
1212	 that it will also disable the helpful warning if a program
1213	 tries to use a vsyscall.  With this option set to N, offending
1214	 programs will just segfault, citing addresses of the form
1215	 0xffffffffff600?00.
1216
1217	 This option is required by many programs built before 2013, and
1218	 care should be used even with newer programs if set to N.
1219
1220	 Disabling this option saves about 7K of kernel size and
1221	 possibly 4K of additional runtime pagetable memory.
1222
1223config X86_IOPL_IOPERM
1224	bool "IOPERM and IOPL Emulation"
1225	default y
1226	help
1227	  This enables the ioperm() and iopl() syscalls which are necessary
1228	  for legacy applications.
1229
1230	  Legacy IOPL support is an overbroad mechanism which allows user
1231	  space aside of accessing all 65536 I/O ports also to disable
1232	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1233	  capabilities and permission from potentially active security
1234	  modules.
1235
1236	  The emulation restricts the functionality of the syscall to
1237	  only allowing the full range I/O port access, but prevents the
1238	  ability to disable interrupts from user space which would be
1239	  granted if the hardware IOPL mechanism would be used.
1240
1241config TOSHIBA
1242	tristate "Toshiba Laptop support"
1243	depends on X86_32
1244	help
1245	  This adds a driver to safely access the System Management Mode of
1246	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1247	  not work on models with a Phoenix BIOS. The System Management Mode
1248	  is used to set the BIOS and power saving options on Toshiba portables.
1249
1250	  For information on utilities to make use of this driver see the
1251	  Toshiba Linux utilities web site at:
1252	  <http://www.buzzard.org.uk/toshiba/>.
1253
1254	  Say Y if you intend to run this kernel on a Toshiba portable.
1255	  Say N otherwise.
1256
1257config I8K
1258	tristate "Dell i8k legacy laptop support"
1259	select HWMON
1260	select SENSORS_DELL_SMM
1261	help
1262	  This option enables legacy /proc/i8k userspace interface in hwmon
1263	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1264	  temperature and allows controlling fan speeds of Dell laptops via
1265	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1266	  it reports also power and hotkey status. For fan speed control is
1267	  needed userspace package i8kutils.
1268
1269	  Say Y if you intend to run this kernel on old Dell laptops or want to
1270	  use userspace package i8kutils.
1271	  Say N otherwise.
1272
1273config X86_REBOOTFIXUPS
1274	bool "Enable X86 board specific fixups for reboot"
1275	depends on X86_32
1276	help
1277	  This enables chipset and/or board specific fixups to be done
1278	  in order to get reboot to work correctly. This is only needed on
1279	  some combinations of hardware and BIOS. The symptom, for which
1280	  this config is intended, is when reboot ends with a stalled/hung
1281	  system.
1282
1283	  Currently, the only fixup is for the Geode machines using
1284	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1285
1286	  Say Y if you want to enable the fixup. Currently, it's safe to
1287	  enable this option even if you don't need it.
1288	  Say N otherwise.
1289
1290config MICROCODE
1291	bool "CPU microcode loading support"
1292	default y
1293	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1294	help
1295	  If you say Y here, you will be able to update the microcode on
1296	  Intel and AMD processors. The Intel support is for the IA32 family,
1297	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1298	  AMD support is for families 0x10 and later. You will obviously need
1299	  the actual microcode binary data itself which is not shipped with
1300	  the Linux kernel.
1301
1302	  The preferred method to load microcode from a detached initrd is described
1303	  in Documentation/x86/microcode.rst. For that you need to enable
1304	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1305	  initrd for microcode blobs.
1306
1307	  In addition, you can build the microcode into the kernel. For that you
1308	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1309	  config option.
1310
1311config MICROCODE_INTEL
1312	bool "Intel microcode loading support"
1313	depends on MICROCODE
1314	default MICROCODE
1315	help
1316	  This options enables microcode patch loading support for Intel
1317	  processors.
1318
1319	  For the current Intel microcode data package go to
1320	  <https://downloadcenter.intel.com> and search for
1321	  'Linux Processor Microcode Data File'.
1322
1323config MICROCODE_AMD
1324	bool "AMD microcode loading support"
1325	depends on MICROCODE
1326	help
1327	  If you select this option, microcode patch loading support for AMD
1328	  processors will be enabled.
1329
1330config MICROCODE_OLD_INTERFACE
1331	bool "Ancient loading interface (DEPRECATED)"
1332	default n
1333	depends on MICROCODE
1334	help
1335	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1336	  which was used by userspace tools like iucode_tool and microcode.ctl.
1337	  It is inadequate because it runs too late to be able to properly
1338	  load microcode on a machine and it needs special tools. Instead, you
1339	  should've switched to the early loading method with the initrd or
1340	  builtin microcode by now: Documentation/x86/microcode.rst
1341
1342config X86_MSR
1343	tristate "/dev/cpu/*/msr - Model-specific register support"
1344	help
1345	  This device gives privileged processes access to the x86
1346	  Model-Specific Registers (MSRs).  It is a character device with
1347	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1348	  MSR accesses are directed to a specific CPU on multi-processor
1349	  systems.
1350
1351config X86_CPUID
1352	tristate "/dev/cpu/*/cpuid - CPU information support"
1353	help
1354	  This device gives processes access to the x86 CPUID instruction to
1355	  be executed on a specific processor.  It is a character device
1356	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1357	  /dev/cpu/31/cpuid.
1358
1359choice
1360	prompt "High Memory Support"
1361	default HIGHMEM4G
1362	depends on X86_32
1363
1364config NOHIGHMEM
1365	bool "off"
1366	help
1367	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1368	  However, the address space of 32-bit x86 processors is only 4
1369	  Gigabytes large. That means that, if you have a large amount of
1370	  physical memory, not all of it can be "permanently mapped" by the
1371	  kernel. The physical memory that's not permanently mapped is called
1372	  "high memory".
1373
1374	  If you are compiling a kernel which will never run on a machine with
1375	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1376	  choice and suitable for most users). This will result in a "3GB/1GB"
1377	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1378	  space and the remaining part of the 4GB virtual memory space is used
1379	  by the kernel to permanently map as much physical memory as
1380	  possible.
1381
1382	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1383	  answer "4GB" here.
1384
1385	  If more than 4 Gigabytes is used then answer "64GB" here. This
1386	  selection turns Intel PAE (Physical Address Extension) mode on.
1387	  PAE implements 3-level paging on IA32 processors. PAE is fully
1388	  supported by Linux, PAE mode is implemented on all recent Intel
1389	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1390	  then the kernel will not boot on CPUs that don't support PAE!
1391
1392	  The actual amount of total physical memory will either be
1393	  auto detected or can be forced by using a kernel command line option
1394	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1395	  your boot loader (lilo or loadlin) about how to pass options to the
1396	  kernel at boot time.)
1397
1398	  If unsure, say "off".
1399
1400config HIGHMEM4G
1401	bool "4GB"
1402	help
1403	  Select this if you have a 32-bit processor and between 1 and 4
1404	  gigabytes of physical RAM.
1405
1406config HIGHMEM64G
1407	bool "64GB"
1408	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1409	select X86_PAE
1410	help
1411	  Select this if you have a 32-bit processor and more than 4
1412	  gigabytes of physical RAM.
1413
1414endchoice
1415
1416choice
1417	prompt "Memory split" if EXPERT
1418	default VMSPLIT_3G
1419	depends on X86_32
1420	help
1421	  Select the desired split between kernel and user memory.
1422
1423	  If the address range available to the kernel is less than the
1424	  physical memory installed, the remaining memory will be available
1425	  as "high memory". Accessing high memory is a little more costly
1426	  than low memory, as it needs to be mapped into the kernel first.
1427	  Note that increasing the kernel address space limits the range
1428	  available to user programs, making the address space there
1429	  tighter.  Selecting anything other than the default 3G/1G split
1430	  will also likely make your kernel incompatible with binary-only
1431	  kernel modules.
1432
1433	  If you are not absolutely sure what you are doing, leave this
1434	  option alone!
1435
1436	config VMSPLIT_3G
1437		bool "3G/1G user/kernel split"
1438	config VMSPLIT_3G_OPT
1439		depends on !X86_PAE
1440		bool "3G/1G user/kernel split (for full 1G low memory)"
1441	config VMSPLIT_2G
1442		bool "2G/2G user/kernel split"
1443	config VMSPLIT_2G_OPT
1444		depends on !X86_PAE
1445		bool "2G/2G user/kernel split (for full 2G low memory)"
1446	config VMSPLIT_1G
1447		bool "1G/3G user/kernel split"
1448endchoice
1449
1450config PAGE_OFFSET
1451	hex
1452	default 0xB0000000 if VMSPLIT_3G_OPT
1453	default 0x80000000 if VMSPLIT_2G
1454	default 0x78000000 if VMSPLIT_2G_OPT
1455	default 0x40000000 if VMSPLIT_1G
1456	default 0xC0000000
1457	depends on X86_32
1458
1459config HIGHMEM
1460	def_bool y
1461	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1462
1463config X86_PAE
1464	bool "PAE (Physical Address Extension) Support"
1465	depends on X86_32 && !HIGHMEM4G
1466	select PHYS_ADDR_T_64BIT
1467	select SWIOTLB
1468	help
1469	  PAE is required for NX support, and furthermore enables
1470	  larger swapspace support for non-overcommit purposes. It
1471	  has the cost of more pagetable lookup overhead, and also
1472	  consumes more pagetable space per process.
1473
1474config X86_5LEVEL
1475	bool "Enable 5-level page tables support"
1476	default y
1477	select DYNAMIC_MEMORY_LAYOUT
1478	select SPARSEMEM_VMEMMAP
1479	depends on X86_64
1480	help
1481	  5-level paging enables access to larger address space:
1482	  upto 128 PiB of virtual address space and 4 PiB of
1483	  physical address space.
1484
1485	  It will be supported by future Intel CPUs.
1486
1487	  A kernel with the option enabled can be booted on machines that
1488	  support 4- or 5-level paging.
1489
1490	  See Documentation/x86/x86_64/5level-paging.rst for more
1491	  information.
1492
1493	  Say N if unsure.
1494
1495config X86_DIRECT_GBPAGES
1496	def_bool y
1497	depends on X86_64
1498	help
1499	  Certain kernel features effectively disable kernel
1500	  linear 1 GB mappings (even if the CPU otherwise
1501	  supports them), so don't confuse the user by printing
1502	  that we have them enabled.
1503
1504config X86_CPA_STATISTICS
1505	bool "Enable statistic for Change Page Attribute"
1506	depends on DEBUG_FS
1507	help
1508	  Expose statistics about the Change Page Attribute mechanism, which
1509	  helps to determine the effectiveness of preserving large and huge
1510	  page mappings when mapping protections are changed.
1511
1512config AMD_MEM_ENCRYPT
1513	bool "AMD Secure Memory Encryption (SME) support"
1514	depends on X86_64 && CPU_SUP_AMD
1515	select DMA_COHERENT_POOL
1516	select DYNAMIC_PHYSICAL_MASK
1517	select ARCH_USE_MEMREMAP_PROT
1518	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1519	select INSTRUCTION_DECODER
1520	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1521	help
1522	  Say yes to enable support for the encryption of system memory.
1523	  This requires an AMD processor that supports Secure Memory
1524	  Encryption (SME).
1525
1526config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1527	bool "Activate AMD Secure Memory Encryption (SME) by default"
1528	default y
1529	depends on AMD_MEM_ENCRYPT
1530	help
1531	  Say yes to have system memory encrypted by default if running on
1532	  an AMD processor that supports Secure Memory Encryption (SME).
1533
1534	  If set to Y, then the encryption of system memory can be
1535	  deactivated with the mem_encrypt=off command line option.
1536
1537	  If set to N, then the encryption of system memory can be
1538	  activated with the mem_encrypt=on command line option.
1539
1540# Common NUMA Features
1541config NUMA
1542	bool "NUMA Memory Allocation and Scheduler Support"
1543	depends on SMP
1544	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1545	default y if X86_BIGSMP
1546	help
1547	  Enable NUMA (Non-Uniform Memory Access) support.
1548
1549	  The kernel will try to allocate memory used by a CPU on the
1550	  local memory controller of the CPU and add some more
1551	  NUMA awareness to the kernel.
1552
1553	  For 64-bit this is recommended if the system is Intel Core i7
1554	  (or later), AMD Opteron, or EM64T NUMA.
1555
1556	  For 32-bit this is only needed if you boot a 32-bit
1557	  kernel on a 64-bit NUMA platform.
1558
1559	  Otherwise, you should say N.
1560
1561config AMD_NUMA
1562	def_bool y
1563	prompt "Old style AMD Opteron NUMA detection"
1564	depends on X86_64 && NUMA && PCI
1565	help
1566	  Enable AMD NUMA node topology detection.  You should say Y here if
1567	  you have a multi processor AMD system. This uses an old method to
1568	  read the NUMA configuration directly from the builtin Northbridge
1569	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1570	  which also takes priority if both are compiled in.
1571
1572config X86_64_ACPI_NUMA
1573	def_bool y
1574	prompt "ACPI NUMA detection"
1575	depends on X86_64 && NUMA && ACPI && PCI
1576	select ACPI_NUMA
1577	help
1578	  Enable ACPI SRAT based node topology detection.
1579
1580config NUMA_EMU
1581	bool "NUMA emulation"
1582	depends on NUMA
1583	help
1584	  Enable NUMA emulation. A flat machine will be split
1585	  into virtual nodes when booted with "numa=fake=N", where N is the
1586	  number of nodes. This is only useful for debugging.
1587
1588config NODES_SHIFT
1589	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1590	range 1 10
1591	default "10" if MAXSMP
1592	default "6" if X86_64
1593	default "3"
1594	depends on NUMA
1595	help
1596	  Specify the maximum number of NUMA Nodes available on the target
1597	  system.  Increases memory reserved to accommodate various tables.
1598
1599config ARCH_FLATMEM_ENABLE
1600	def_bool y
1601	depends on X86_32 && !NUMA
1602
1603config ARCH_SPARSEMEM_ENABLE
1604	def_bool y
1605	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1606	select SPARSEMEM_STATIC if X86_32
1607	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1608
1609config ARCH_SPARSEMEM_DEFAULT
1610	def_bool X86_64 || (NUMA && X86_32)
1611
1612config ARCH_SELECT_MEMORY_MODEL
1613	def_bool y
1614	depends on ARCH_SPARSEMEM_ENABLE
1615
1616config ARCH_MEMORY_PROBE
1617	bool "Enable sysfs memory/probe interface"
1618	depends on X86_64 && MEMORY_HOTPLUG
1619	help
1620	  This option enables a sysfs memory/probe interface for testing.
1621	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1622	  If you are unsure how to answer this question, answer N.
1623
1624config ARCH_PROC_KCORE_TEXT
1625	def_bool y
1626	depends on X86_64 && PROC_KCORE
1627
1628config ILLEGAL_POINTER_VALUE
1629	hex
1630	default 0 if X86_32
1631	default 0xdead000000000000 if X86_64
1632
1633config X86_PMEM_LEGACY_DEVICE
1634	bool
1635
1636config X86_PMEM_LEGACY
1637	tristate "Support non-standard NVDIMMs and ADR protected memory"
1638	depends on PHYS_ADDR_T_64BIT
1639	depends on BLK_DEV
1640	select X86_PMEM_LEGACY_DEVICE
1641	select NUMA_KEEP_MEMINFO if NUMA
1642	select LIBNVDIMM
1643	help
1644	  Treat memory marked using the non-standard e820 type of 12 as used
1645	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1646	  The kernel will offer these regions to the 'pmem' driver so
1647	  they can be used for persistent storage.
1648
1649	  Say Y if unsure.
1650
1651config HIGHPTE
1652	bool "Allocate 3rd-level pagetables from highmem"
1653	depends on HIGHMEM
1654	help
1655	  The VM uses one page table entry for each page of physical memory.
1656	  For systems with a lot of RAM, this can be wasteful of precious
1657	  low memory.  Setting this option will put user-space page table
1658	  entries in high memory.
1659
1660config X86_CHECK_BIOS_CORRUPTION
1661	bool "Check for low memory corruption"
1662	help
1663	  Periodically check for memory corruption in low memory, which
1664	  is suspected to be caused by BIOS.  Even when enabled in the
1665	  configuration, it is disabled at runtime.  Enable it by
1666	  setting "memory_corruption_check=1" on the kernel command
1667	  line.  By default it scans the low 64k of memory every 60
1668	  seconds; see the memory_corruption_check_size and
1669	  memory_corruption_check_period parameters in
1670	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1671
1672	  When enabled with the default parameters, this option has
1673	  almost no overhead, as it reserves a relatively small amount
1674	  of memory and scans it infrequently.  It both detects corruption
1675	  and prevents it from affecting the running system.
1676
1677	  It is, however, intended as a diagnostic tool; if repeatable
1678	  BIOS-originated corruption always affects the same memory,
1679	  you can use memmap= to prevent the kernel from using that
1680	  memory.
1681
1682config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1683	bool "Set the default setting of memory_corruption_check"
1684	depends on X86_CHECK_BIOS_CORRUPTION
1685	default y
1686	help
1687	  Set whether the default state of memory_corruption_check is
1688	  on or off.
1689
1690config MATH_EMULATION
1691	bool
1692	depends on MODIFY_LDT_SYSCALL
1693	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1694	help
1695	  Linux can emulate a math coprocessor (used for floating point
1696	  operations) if you don't have one. 486DX and Pentium processors have
1697	  a math coprocessor built in, 486SX and 386 do not, unless you added
1698	  a 487DX or 387, respectively. (The messages during boot time can
1699	  give you some hints here ["man dmesg"].) Everyone needs either a
1700	  coprocessor or this emulation.
1701
1702	  If you don't have a math coprocessor, you need to say Y here; if you
1703	  say Y here even though you have a coprocessor, the coprocessor will
1704	  be used nevertheless. (This behavior can be changed with the kernel
1705	  command line option "no387", which comes handy if your coprocessor
1706	  is broken. Try "man bootparam" or see the documentation of your boot
1707	  loader (lilo or loadlin) about how to pass options to the kernel at
1708	  boot time.) This means that it is a good idea to say Y here if you
1709	  intend to use this kernel on different machines.
1710
1711	  More information about the internals of the Linux math coprocessor
1712	  emulation can be found in <file:arch/x86/math-emu/README>.
1713
1714	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1715	  kernel, it won't hurt.
1716
1717config MTRR
1718	def_bool y
1719	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1720	help
1721	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1722	  the Memory Type Range Registers (MTRRs) may be used to control
1723	  processor access to memory ranges. This is most useful if you have
1724	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1725	  allows bus write transfers to be combined into a larger transfer
1726	  before bursting over the PCI/AGP bus. This can increase performance
1727	  of image write operations 2.5 times or more. Saying Y here creates a
1728	  /proc/mtrr file which may be used to manipulate your processor's
1729	  MTRRs. Typically the X server should use this.
1730
1731	  This code has a reasonably generic interface so that similar
1732	  control registers on other processors can be easily supported
1733	  as well:
1734
1735	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1736	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1737	  these, the ARRs are used to emulate the MTRRs.
1738	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1739	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1740	  write-combining. All of these processors are supported by this code
1741	  and it makes sense to say Y here if you have one of them.
1742
1743	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1744	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1745	  can lead to all sorts of problems, so it's good to say Y here.
1746
1747	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1748	  just add about 9 KB to your kernel.
1749
1750	  See <file:Documentation/x86/mtrr.rst> for more information.
1751
1752config MTRR_SANITIZER
1753	def_bool y
1754	prompt "MTRR cleanup support"
1755	depends on MTRR
1756	help
1757	  Convert MTRR layout from continuous to discrete, so X drivers can
1758	  add writeback entries.
1759
1760	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1761	  The largest mtrr entry size for a continuous block can be set with
1762	  mtrr_chunk_size.
1763
1764	  If unsure, say Y.
1765
1766config MTRR_SANITIZER_ENABLE_DEFAULT
1767	int "MTRR cleanup enable value (0-1)"
1768	range 0 1
1769	default "0"
1770	depends on MTRR_SANITIZER
1771	help
1772	  Enable mtrr cleanup default value
1773
1774config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1775	int "MTRR cleanup spare reg num (0-7)"
1776	range 0 7
1777	default "1"
1778	depends on MTRR_SANITIZER
1779	help
1780	  mtrr cleanup spare entries default, it can be changed via
1781	  mtrr_spare_reg_nr=N on the kernel command line.
1782
1783config X86_PAT
1784	def_bool y
1785	prompt "x86 PAT support" if EXPERT
1786	depends on MTRR
1787	help
1788	  Use PAT attributes to setup page level cache control.
1789
1790	  PATs are the modern equivalents of MTRRs and are much more
1791	  flexible than MTRRs.
1792
1793	  Say N here if you see bootup problems (boot crash, boot hang,
1794	  spontaneous reboots) or a non-working video driver.
1795
1796	  If unsure, say Y.
1797
1798config ARCH_USES_PG_UNCACHED
1799	def_bool y
1800	depends on X86_PAT
1801
1802config ARCH_RANDOM
1803	def_bool y
1804	prompt "x86 architectural random number generator" if EXPERT
1805	help
1806	  Enable the x86 architectural RDRAND instruction
1807	  (Intel Bull Mountain technology) to generate random numbers.
1808	  If supported, this is a high bandwidth, cryptographically
1809	  secure hardware random number generator.
1810
1811config X86_SMAP
1812	def_bool y
1813	prompt "Supervisor Mode Access Prevention" if EXPERT
1814	help
1815	  Supervisor Mode Access Prevention (SMAP) is a security
1816	  feature in newer Intel processors.  There is a small
1817	  performance cost if this enabled and turned on; there is
1818	  also a small increase in the kernel size if this is enabled.
1819
1820	  If unsure, say Y.
1821
1822config X86_UMIP
1823	def_bool y
1824	prompt "User Mode Instruction Prevention" if EXPERT
1825	help
1826	  User Mode Instruction Prevention (UMIP) is a security feature in
1827	  some x86 processors. If enabled, a general protection fault is
1828	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1829	  executed in user mode. These instructions unnecessarily expose
1830	  information about the hardware state.
1831
1832	  The vast majority of applications do not use these instructions.
1833	  For the very few that do, software emulation is provided in
1834	  specific cases in protected and virtual-8086 modes. Emulated
1835	  results are dummy.
1836
1837config X86_INTEL_MEMORY_PROTECTION_KEYS
1838	prompt "Memory Protection Keys"
1839	def_bool y
1840	# Note: only available in 64-bit mode
1841	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1842	select ARCH_USES_HIGH_VMA_FLAGS
1843	select ARCH_HAS_PKEYS
1844	help
1845	  Memory Protection Keys provides a mechanism for enforcing
1846	  page-based protections, but without requiring modification of the
1847	  page tables when an application changes protection domains.
1848
1849	  For details, see Documentation/core-api/protection-keys.rst
1850
1851	  If unsure, say y.
1852
1853choice
1854	prompt "TSX enable mode"
1855	depends on CPU_SUP_INTEL
1856	default X86_INTEL_TSX_MODE_OFF
1857	help
1858	  Intel's TSX (Transactional Synchronization Extensions) feature
1859	  allows to optimize locking protocols through lock elision which
1860	  can lead to a noticeable performance boost.
1861
1862	  On the other hand it has been shown that TSX can be exploited
1863	  to form side channel attacks (e.g. TAA) and chances are there
1864	  will be more of those attacks discovered in the future.
1865
1866	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1867	  might override this decision by tsx=on the command line parameter.
1868	  Even with TSX enabled, the kernel will attempt to enable the best
1869	  possible TAA mitigation setting depending on the microcode available
1870	  for the particular machine.
1871
1872	  This option allows to set the default tsx mode between tsx=on, =off
1873	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1874	  details.
1875
1876	  Say off if not sure, auto if TSX is in use but it should be used on safe
1877	  platforms or on if TSX is in use and the security aspect of tsx is not
1878	  relevant.
1879
1880config X86_INTEL_TSX_MODE_OFF
1881	bool "off"
1882	help
1883	  TSX is disabled if possible - equals to tsx=off command line parameter.
1884
1885config X86_INTEL_TSX_MODE_ON
1886	bool "on"
1887	help
1888	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1889	  line parameter.
1890
1891config X86_INTEL_TSX_MODE_AUTO
1892	bool "auto"
1893	help
1894	  TSX is enabled on TSX capable HW that is believed to be safe against
1895	  side channel attacks- equals the tsx=auto command line parameter.
1896endchoice
1897
1898config X86_SGX
1899	bool "Software Guard eXtensions (SGX)"
1900	depends on X86_64 && CPU_SUP_INTEL
1901	depends on CRYPTO=y
1902	depends on CRYPTO_SHA256=y
1903	select SRCU
1904	select MMU_NOTIFIER
1905	select NUMA_KEEP_MEMINFO if NUMA
1906	help
1907	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1908	  that can be used by applications to set aside private regions of code
1909	  and data, referred to as enclaves. An enclave's private memory can
1910	  only be accessed by code running within the enclave. Accesses from
1911	  outside the enclave, including other enclaves, are disallowed by
1912	  hardware.
1913
1914	  If unsure, say N.
1915
1916config EFI
1917	bool "EFI runtime service support"
1918	depends on ACPI
1919	select UCS2_STRING
1920	select EFI_RUNTIME_WRAPPERS
1921	help
1922	  This enables the kernel to use EFI runtime services that are
1923	  available (such as the EFI variable services).
1924
1925	  This option is only useful on systems that have EFI firmware.
1926	  In addition, you should use the latest ELILO loader available
1927	  at <http://elilo.sourceforge.net> in order to take advantage
1928	  of EFI runtime services. However, even with this option, the
1929	  resultant kernel should continue to boot on existing non-EFI
1930	  platforms.
1931
1932config EFI_STUB
1933	bool "EFI stub support"
1934	depends on EFI && !X86_USE_3DNOW
1935	depends on $(cc-option,-mabi=ms) || X86_32
1936	select RELOCATABLE
1937	help
1938	  This kernel feature allows a bzImage to be loaded directly
1939	  by EFI firmware without the use of a bootloader.
1940
1941	  See Documentation/admin-guide/efi-stub.rst for more information.
1942
1943config EFI_MIXED
1944	bool "EFI mixed-mode support"
1945	depends on EFI_STUB && X86_64
1946	help
1947	   Enabling this feature allows a 64-bit kernel to be booted
1948	   on a 32-bit firmware, provided that your CPU supports 64-bit
1949	   mode.
1950
1951	   Note that it is not possible to boot a mixed-mode enabled
1952	   kernel via the EFI boot stub - a bootloader that supports
1953	   the EFI handover protocol must be used.
1954
1955	   If unsure, say N.
1956
1957source "kernel/Kconfig.hz"
1958
1959config KEXEC
1960	bool "kexec system call"
1961	select KEXEC_CORE
1962	help
1963	  kexec is a system call that implements the ability to shutdown your
1964	  current kernel, and to start another kernel.  It is like a reboot
1965	  but it is independent of the system firmware.   And like a reboot
1966	  you can start any kernel with it, not just Linux.
1967
1968	  The name comes from the similarity to the exec system call.
1969
1970	  It is an ongoing process to be certain the hardware in a machine
1971	  is properly shutdown, so do not be surprised if this code does not
1972	  initially work for you.  As of this writing the exact hardware
1973	  interface is strongly in flux, so no good recommendation can be
1974	  made.
1975
1976config KEXEC_FILE
1977	bool "kexec file based system call"
1978	select KEXEC_CORE
1979	select BUILD_BIN2C
1980	depends on X86_64
1981	depends on CRYPTO=y
1982	depends on CRYPTO_SHA256=y
1983	help
1984	  This is new version of kexec system call. This system call is
1985	  file based and takes file descriptors as system call argument
1986	  for kernel and initramfs as opposed to list of segments as
1987	  accepted by previous system call.
1988
1989config ARCH_HAS_KEXEC_PURGATORY
1990	def_bool KEXEC_FILE
1991
1992config KEXEC_SIG
1993	bool "Verify kernel signature during kexec_file_load() syscall"
1994	depends on KEXEC_FILE
1995	help
1996
1997	  This option makes the kexec_file_load() syscall check for a valid
1998	  signature of the kernel image.  The image can still be loaded without
1999	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2000	  there's a signature that we can check, then it must be valid.
2001
2002	  In addition to this option, you need to enable signature
2003	  verification for the corresponding kernel image type being
2004	  loaded in order for this to work.
2005
2006config KEXEC_SIG_FORCE
2007	bool "Require a valid signature in kexec_file_load() syscall"
2008	depends on KEXEC_SIG
2009	help
2010	  This option makes kernel signature verification mandatory for
2011	  the kexec_file_load() syscall.
2012
2013config KEXEC_BZIMAGE_VERIFY_SIG
2014	bool "Enable bzImage signature verification support"
2015	depends on KEXEC_SIG
2016	depends on SIGNED_PE_FILE_VERIFICATION
2017	select SYSTEM_TRUSTED_KEYRING
2018	help
2019	  Enable bzImage signature verification support.
2020
2021config CRASH_DUMP
2022	bool "kernel crash dumps"
2023	depends on X86_64 || (X86_32 && HIGHMEM)
2024	help
2025	  Generate crash dump after being started by kexec.
2026	  This should be normally only set in special crash dump kernels
2027	  which are loaded in the main kernel with kexec-tools into
2028	  a specially reserved region and then later executed after
2029	  a crash by kdump/kexec. The crash dump kernel must be compiled
2030	  to a memory address not used by the main kernel or BIOS using
2031	  PHYSICAL_START, or it must be built as a relocatable image
2032	  (CONFIG_RELOCATABLE=y).
2033	  For more details see Documentation/admin-guide/kdump/kdump.rst
2034
2035config KEXEC_JUMP
2036	bool "kexec jump"
2037	depends on KEXEC && HIBERNATION
2038	help
2039	  Jump between original kernel and kexeced kernel and invoke
2040	  code in physical address mode via KEXEC
2041
2042config PHYSICAL_START
2043	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2044	default "0x1000000"
2045	help
2046	  This gives the physical address where the kernel is loaded.
2047
2048	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2049	  bzImage will decompress itself to above physical address and
2050	  run from there. Otherwise, bzImage will run from the address where
2051	  it has been loaded by the boot loader and will ignore above physical
2052	  address.
2053
2054	  In normal kdump cases one does not have to set/change this option
2055	  as now bzImage can be compiled as a completely relocatable image
2056	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2057	  address. This option is mainly useful for the folks who don't want
2058	  to use a bzImage for capturing the crash dump and want to use a
2059	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2060	  to be specifically compiled to run from a specific memory area
2061	  (normally a reserved region) and this option comes handy.
2062
2063	  So if you are using bzImage for capturing the crash dump,
2064	  leave the value here unchanged to 0x1000000 and set
2065	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2066	  for capturing the crash dump change this value to start of
2067	  the reserved region.  In other words, it can be set based on
2068	  the "X" value as specified in the "crashkernel=YM@XM"
2069	  command line boot parameter passed to the panic-ed
2070	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2071	  for more details about crash dumps.
2072
2073	  Usage of bzImage for capturing the crash dump is recommended as
2074	  one does not have to build two kernels. Same kernel can be used
2075	  as production kernel and capture kernel. Above option should have
2076	  gone away after relocatable bzImage support is introduced. But it
2077	  is present because there are users out there who continue to use
2078	  vmlinux for dump capture. This option should go away down the
2079	  line.
2080
2081	  Don't change this unless you know what you are doing.
2082
2083config RELOCATABLE
2084	bool "Build a relocatable kernel"
2085	default y
2086	help
2087	  This builds a kernel image that retains relocation information
2088	  so it can be loaded someplace besides the default 1MB.
2089	  The relocations tend to make the kernel binary about 10% larger,
2090	  but are discarded at runtime.
2091
2092	  One use is for the kexec on panic case where the recovery kernel
2093	  must live at a different physical address than the primary
2094	  kernel.
2095
2096	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2097	  it has been loaded at and the compile time physical address
2098	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2099
2100config RANDOMIZE_BASE
2101	bool "Randomize the address of the kernel image (KASLR)"
2102	depends on RELOCATABLE
2103	default y
2104	help
2105	  In support of Kernel Address Space Layout Randomization (KASLR),
2106	  this randomizes the physical address at which the kernel image
2107	  is decompressed and the virtual address where the kernel
2108	  image is mapped, as a security feature that deters exploit
2109	  attempts relying on knowledge of the location of kernel
2110	  code internals.
2111
2112	  On 64-bit, the kernel physical and virtual addresses are
2113	  randomized separately. The physical address will be anywhere
2114	  between 16MB and the top of physical memory (up to 64TB). The
2115	  virtual address will be randomized from 16MB up to 1GB (9 bits
2116	  of entropy). Note that this also reduces the memory space
2117	  available to kernel modules from 1.5GB to 1GB.
2118
2119	  On 32-bit, the kernel physical and virtual addresses are
2120	  randomized together. They will be randomized from 16MB up to
2121	  512MB (8 bits of entropy).
2122
2123	  Entropy is generated using the RDRAND instruction if it is
2124	  supported. If RDTSC is supported, its value is mixed into
2125	  the entropy pool as well. If neither RDRAND nor RDTSC are
2126	  supported, then entropy is read from the i8254 timer. The
2127	  usable entropy is limited by the kernel being built using
2128	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2129	  minimum of 2MB. As a result, only 10 bits of entropy are
2130	  theoretically possible, but the implementations are further
2131	  limited due to memory layouts.
2132
2133	  If unsure, say Y.
2134
2135# Relocation on x86 needs some additional build support
2136config X86_NEED_RELOCS
2137	def_bool y
2138	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2139
2140config PHYSICAL_ALIGN
2141	hex "Alignment value to which kernel should be aligned"
2142	default "0x200000"
2143	range 0x2000 0x1000000 if X86_32
2144	range 0x200000 0x1000000 if X86_64
2145	help
2146	  This value puts the alignment restrictions on physical address
2147	  where kernel is loaded and run from. Kernel is compiled for an
2148	  address which meets above alignment restriction.
2149
2150	  If bootloader loads the kernel at a non-aligned address and
2151	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2152	  address aligned to above value and run from there.
2153
2154	  If bootloader loads the kernel at a non-aligned address and
2155	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2156	  load address and decompress itself to the address it has been
2157	  compiled for and run from there. The address for which kernel is
2158	  compiled already meets above alignment restrictions. Hence the
2159	  end result is that kernel runs from a physical address meeting
2160	  above alignment restrictions.
2161
2162	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2163	  this value must be a multiple of 0x200000.
2164
2165	  Don't change this unless you know what you are doing.
2166
2167config DYNAMIC_MEMORY_LAYOUT
2168	bool
2169	help
2170	  This option makes base addresses of vmalloc and vmemmap as well as
2171	  __PAGE_OFFSET movable during boot.
2172
2173config RANDOMIZE_MEMORY
2174	bool "Randomize the kernel memory sections"
2175	depends on X86_64
2176	depends on RANDOMIZE_BASE
2177	select DYNAMIC_MEMORY_LAYOUT
2178	default RANDOMIZE_BASE
2179	help
2180	   Randomizes the base virtual address of kernel memory sections
2181	   (physical memory mapping, vmalloc & vmemmap). This security feature
2182	   makes exploits relying on predictable memory locations less reliable.
2183
2184	   The order of allocations remains unchanged. Entropy is generated in
2185	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2186	   configuration have in average 30,000 different possible virtual
2187	   addresses for each memory section.
2188
2189	   If unsure, say Y.
2190
2191config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2192	hex "Physical memory mapping padding" if EXPERT
2193	depends on RANDOMIZE_MEMORY
2194	default "0xa" if MEMORY_HOTPLUG
2195	default "0x0"
2196	range 0x1 0x40 if MEMORY_HOTPLUG
2197	range 0x0 0x40
2198	help
2199	   Define the padding in terabytes added to the existing physical
2200	   memory size during kernel memory randomization. It is useful
2201	   for memory hotplug support but reduces the entropy available for
2202	   address randomization.
2203
2204	   If unsure, leave at the default value.
2205
2206config HOTPLUG_CPU
2207	def_bool y
2208	depends on SMP
2209
2210config BOOTPARAM_HOTPLUG_CPU0
2211	bool "Set default setting of cpu0_hotpluggable"
2212	depends on HOTPLUG_CPU
2213	help
2214	  Set whether default state of cpu0_hotpluggable is on or off.
2215
2216	  Say Y here to enable CPU0 hotplug by default. If this switch
2217	  is turned on, there is no need to give cpu0_hotplug kernel
2218	  parameter and the CPU0 hotplug feature is enabled by default.
2219
2220	  Please note: there are two known CPU0 dependencies if you want
2221	  to enable the CPU0 hotplug feature either by this switch or by
2222	  cpu0_hotplug kernel parameter.
2223
2224	  First, resume from hibernate or suspend always starts from CPU0.
2225	  So hibernate and suspend are prevented if CPU0 is offline.
2226
2227	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2228	  offline if any interrupt can not migrate out of CPU0. There may
2229	  be other CPU0 dependencies.
2230
2231	  Please make sure the dependencies are under your control before
2232	  you enable this feature.
2233
2234	  Say N if you don't want to enable CPU0 hotplug feature by default.
2235	  You still can enable the CPU0 hotplug feature at boot by kernel
2236	  parameter cpu0_hotplug.
2237
2238config DEBUG_HOTPLUG_CPU0
2239	def_bool n
2240	prompt "Debug CPU0 hotplug"
2241	depends on HOTPLUG_CPU
2242	help
2243	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2244	  soon as possible and boots up userspace with CPU0 offlined. User
2245	  can online CPU0 back after boot time.
2246
2247	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2248	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2249	  compilation or giving cpu0_hotplug kernel parameter at boot.
2250
2251	  If unsure, say N.
2252
2253config COMPAT_VDSO
2254	def_bool n
2255	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2256	depends on COMPAT_32
2257	help
2258	  Certain buggy versions of glibc will crash if they are
2259	  presented with a 32-bit vDSO that is not mapped at the address
2260	  indicated in its segment table.
2261
2262	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2263	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2264	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2265	  the only released version with the bug, but OpenSUSE 9
2266	  contains a buggy "glibc 2.3.2".
2267
2268	  The symptom of the bug is that everything crashes on startup, saying:
2269	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2270
2271	  Saying Y here changes the default value of the vdso32 boot
2272	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2273	  This works around the glibc bug but hurts performance.
2274
2275	  If unsure, say N: if you are compiling your own kernel, you
2276	  are unlikely to be using a buggy version of glibc.
2277
2278choice
2279	prompt "vsyscall table for legacy applications"
2280	depends on X86_64
2281	default LEGACY_VSYSCALL_XONLY
2282	help
2283	  Legacy user code that does not know how to find the vDSO expects
2284	  to be able to issue three syscalls by calling fixed addresses in
2285	  kernel space. Since this location is not randomized with ASLR,
2286	  it can be used to assist security vulnerability exploitation.
2287
2288	  This setting can be changed at boot time via the kernel command
2289	  line parameter vsyscall=[emulate|xonly|none].
2290
2291	  On a system with recent enough glibc (2.14 or newer) and no
2292	  static binaries, you can say None without a performance penalty
2293	  to improve security.
2294
2295	  If unsure, select "Emulate execution only".
2296
2297	config LEGACY_VSYSCALL_EMULATE
2298		bool "Full emulation"
2299		help
2300		  The kernel traps and emulates calls into the fixed vsyscall
2301		  address mapping. This makes the mapping non-executable, but
2302		  it still contains readable known contents, which could be
2303		  used in certain rare security vulnerability exploits. This
2304		  configuration is recommended when using legacy userspace
2305		  that still uses vsyscalls along with legacy binary
2306		  instrumentation tools that require code to be readable.
2307
2308		  An example of this type of legacy userspace is running
2309		  Pin on an old binary that still uses vsyscalls.
2310
2311	config LEGACY_VSYSCALL_XONLY
2312		bool "Emulate execution only"
2313		help
2314		  The kernel traps and emulates calls into the fixed vsyscall
2315		  address mapping and does not allow reads.  This
2316		  configuration is recommended when userspace might use the
2317		  legacy vsyscall area but support for legacy binary
2318		  instrumentation of legacy code is not needed.  It mitigates
2319		  certain uses of the vsyscall area as an ASLR-bypassing
2320		  buffer.
2321
2322	config LEGACY_VSYSCALL_NONE
2323		bool "None"
2324		help
2325		  There will be no vsyscall mapping at all. This will
2326		  eliminate any risk of ASLR bypass due to the vsyscall
2327		  fixed address mapping. Attempts to use the vsyscalls
2328		  will be reported to dmesg, so that either old or
2329		  malicious userspace programs can be identified.
2330
2331endchoice
2332
2333config CMDLINE_BOOL
2334	bool "Built-in kernel command line"
2335	help
2336	  Allow for specifying boot arguments to the kernel at
2337	  build time.  On some systems (e.g. embedded ones), it is
2338	  necessary or convenient to provide some or all of the
2339	  kernel boot arguments with the kernel itself (that is,
2340	  to not rely on the boot loader to provide them.)
2341
2342	  To compile command line arguments into the kernel,
2343	  set this option to 'Y', then fill in the
2344	  boot arguments in CONFIG_CMDLINE.
2345
2346	  Systems with fully functional boot loaders (i.e. non-embedded)
2347	  should leave this option set to 'N'.
2348
2349config CMDLINE
2350	string "Built-in kernel command string"
2351	depends on CMDLINE_BOOL
2352	default ""
2353	help
2354	  Enter arguments here that should be compiled into the kernel
2355	  image and used at boot time.  If the boot loader provides a
2356	  command line at boot time, it is appended to this string to
2357	  form the full kernel command line, when the system boots.
2358
2359	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2360	  change this behavior.
2361
2362	  In most cases, the command line (whether built-in or provided
2363	  by the boot loader) should specify the device for the root
2364	  file system.
2365
2366config CMDLINE_OVERRIDE
2367	bool "Built-in command line overrides boot loader arguments"
2368	depends on CMDLINE_BOOL && CMDLINE != ""
2369	help
2370	  Set this option to 'Y' to have the kernel ignore the boot loader
2371	  command line, and use ONLY the built-in command line.
2372
2373	  This is used to work around broken boot loaders.  This should
2374	  be set to 'N' under normal conditions.
2375
2376config MODIFY_LDT_SYSCALL
2377	bool "Enable the LDT (local descriptor table)" if EXPERT
2378	default y
2379	help
2380	  Linux can allow user programs to install a per-process x86
2381	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2382	  call.  This is required to run 16-bit or segmented code such as
2383	  DOSEMU or some Wine programs.  It is also used by some very old
2384	  threading libraries.
2385
2386	  Enabling this feature adds a small amount of overhead to
2387	  context switches and increases the low-level kernel attack
2388	  surface.  Disabling it removes the modify_ldt(2) system call.
2389
2390	  Saying 'N' here may make sense for embedded or server kernels.
2391
2392source "kernel/livepatch/Kconfig"
2393
2394endmenu
2395
2396config ARCH_HAS_ADD_PAGES
2397	def_bool y
2398	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2399
2400config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2401	def_bool y
2402
2403config USE_PERCPU_NUMA_NODE_ID
2404	def_bool y
2405	depends on NUMA
2406
2407menu "Power management and ACPI options"
2408
2409config ARCH_HIBERNATION_HEADER
2410	def_bool y
2411	depends on HIBERNATION
2412
2413source "kernel/power/Kconfig"
2414
2415source "drivers/acpi/Kconfig"
2416
2417config X86_APM_BOOT
2418	def_bool y
2419	depends on APM
2420
2421menuconfig APM
2422	tristate "APM (Advanced Power Management) BIOS support"
2423	depends on X86_32 && PM_SLEEP
2424	help
2425	  APM is a BIOS specification for saving power using several different
2426	  techniques. This is mostly useful for battery powered laptops with
2427	  APM compliant BIOSes. If you say Y here, the system time will be
2428	  reset after a RESUME operation, the /proc/apm device will provide
2429	  battery status information, and user-space programs will receive
2430	  notification of APM "events" (e.g. battery status change).
2431
2432	  If you select "Y" here, you can disable actual use of the APM
2433	  BIOS by passing the "apm=off" option to the kernel at boot time.
2434
2435	  Note that the APM support is almost completely disabled for
2436	  machines with more than one CPU.
2437
2438	  In order to use APM, you will need supporting software. For location
2439	  and more information, read <file:Documentation/power/apm-acpi.rst>
2440	  and the Battery Powered Linux mini-HOWTO, available from
2441	  <http://www.tldp.org/docs.html#howto>.
2442
2443	  This driver does not spin down disk drives (see the hdparm(8)
2444	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2445	  VESA-compliant "green" monitors.
2446
2447	  This driver does not support the TI 4000M TravelMate and the ACER
2448	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2449	  desktop machines also don't have compliant BIOSes, and this driver
2450	  may cause those machines to panic during the boot phase.
2451
2452	  Generally, if you don't have a battery in your machine, there isn't
2453	  much point in using this driver and you should say N. If you get
2454	  random kernel OOPSes or reboots that don't seem to be related to
2455	  anything, try disabling/enabling this option (or disabling/enabling
2456	  APM in your BIOS).
2457
2458	  Some other things you should try when experiencing seemingly random,
2459	  "weird" problems:
2460
2461	  1) make sure that you have enough swap space and that it is
2462	  enabled.
2463	  2) pass the "no-hlt" option to the kernel
2464	  3) switch on floating point emulation in the kernel and pass
2465	  the "no387" option to the kernel
2466	  4) pass the "floppy=nodma" option to the kernel
2467	  5) pass the "mem=4M" option to the kernel (thereby disabling
2468	  all but the first 4 MB of RAM)
2469	  6) make sure that the CPU is not over clocked.
2470	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2471	  8) disable the cache from your BIOS settings
2472	  9) install a fan for the video card or exchange video RAM
2473	  10) install a better fan for the CPU
2474	  11) exchange RAM chips
2475	  12) exchange the motherboard.
2476
2477	  To compile this driver as a module, choose M here: the
2478	  module will be called apm.
2479
2480if APM
2481
2482config APM_IGNORE_USER_SUSPEND
2483	bool "Ignore USER SUSPEND"
2484	help
2485	  This option will ignore USER SUSPEND requests. On machines with a
2486	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2487	  series notebooks, it is necessary to say Y because of a BIOS bug.
2488
2489config APM_DO_ENABLE
2490	bool "Enable PM at boot time"
2491	help
2492	  Enable APM features at boot time. From page 36 of the APM BIOS
2493	  specification: "When disabled, the APM BIOS does not automatically
2494	  power manage devices, enter the Standby State, enter the Suspend
2495	  State, or take power saving steps in response to CPU Idle calls."
2496	  This driver will make CPU Idle calls when Linux is idle (unless this
2497	  feature is turned off -- see "Do CPU IDLE calls", below). This
2498	  should always save battery power, but more complicated APM features
2499	  will be dependent on your BIOS implementation. You may need to turn
2500	  this option off if your computer hangs at boot time when using APM
2501	  support, or if it beeps continuously instead of suspending. Turn
2502	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2503	  T400CDT. This is off by default since most machines do fine without
2504	  this feature.
2505
2506config APM_CPU_IDLE
2507	depends on CPU_IDLE
2508	bool "Make CPU Idle calls when idle"
2509	help
2510	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2511	  On some machines, this can activate improved power savings, such as
2512	  a slowed CPU clock rate, when the machine is idle. These idle calls
2513	  are made after the idle loop has run for some length of time (e.g.,
2514	  333 mS). On some machines, this will cause a hang at boot time or
2515	  whenever the CPU becomes idle. (On machines with more than one CPU,
2516	  this option does nothing.)
2517
2518config APM_DISPLAY_BLANK
2519	bool "Enable console blanking using APM"
2520	help
2521	  Enable console blanking using the APM. Some laptops can use this to
2522	  turn off the LCD backlight when the screen blanker of the Linux
2523	  virtual console blanks the screen. Note that this is only used by
2524	  the virtual console screen blanker, and won't turn off the backlight
2525	  when using the X Window system. This also doesn't have anything to
2526	  do with your VESA-compliant power-saving monitor. Further, this
2527	  option doesn't work for all laptops -- it might not turn off your
2528	  backlight at all, or it might print a lot of errors to the console,
2529	  especially if you are using gpm.
2530
2531config APM_ALLOW_INTS
2532	bool "Allow interrupts during APM BIOS calls"
2533	help
2534	  Normally we disable external interrupts while we are making calls to
2535	  the APM BIOS as a measure to lessen the effects of a badly behaving
2536	  BIOS implementation.  The BIOS should reenable interrupts if it
2537	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2538	  many of the newer IBM Thinkpads.  If you experience hangs when you
2539	  suspend, try setting this to Y.  Otherwise, say N.
2540
2541endif # APM
2542
2543source "drivers/cpufreq/Kconfig"
2544
2545source "drivers/cpuidle/Kconfig"
2546
2547source "drivers/idle/Kconfig"
2548
2549endmenu
2550
2551
2552menu "Bus options (PCI etc.)"
2553
2554choice
2555	prompt "PCI access mode"
2556	depends on X86_32 && PCI
2557	default PCI_GOANY
2558	help
2559	  On PCI systems, the BIOS can be used to detect the PCI devices and
2560	  determine their configuration. However, some old PCI motherboards
2561	  have BIOS bugs and may crash if this is done. Also, some embedded
2562	  PCI-based systems don't have any BIOS at all. Linux can also try to
2563	  detect the PCI hardware directly without using the BIOS.
2564
2565	  With this option, you can specify how Linux should detect the
2566	  PCI devices. If you choose "BIOS", the BIOS will be used,
2567	  if you choose "Direct", the BIOS won't be used, and if you
2568	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2569	  If you choose "Any", the kernel will try MMCONFIG, then the
2570	  direct access method and falls back to the BIOS if that doesn't
2571	  work. If unsure, go with the default, which is "Any".
2572
2573config PCI_GOBIOS
2574	bool "BIOS"
2575
2576config PCI_GOMMCONFIG
2577	bool "MMConfig"
2578
2579config PCI_GODIRECT
2580	bool "Direct"
2581
2582config PCI_GOOLPC
2583	bool "OLPC XO-1"
2584	depends on OLPC
2585
2586config PCI_GOANY
2587	bool "Any"
2588
2589endchoice
2590
2591config PCI_BIOS
2592	def_bool y
2593	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2594
2595# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2596config PCI_DIRECT
2597	def_bool y
2598	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2599
2600config PCI_MMCONFIG
2601	bool "Support mmconfig PCI config space access" if X86_64
2602	default y
2603	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2604	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2605
2606config PCI_OLPC
2607	def_bool y
2608	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2609
2610config PCI_XEN
2611	def_bool y
2612	depends on PCI && XEN
2613
2614config MMCONF_FAM10H
2615	def_bool y
2616	depends on X86_64 && PCI_MMCONFIG && ACPI
2617
2618config PCI_CNB20LE_QUIRK
2619	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2620	depends on PCI
2621	help
2622	  Read the PCI windows out of the CNB20LE host bridge. This allows
2623	  PCI hotplug to work on systems with the CNB20LE chipset which do
2624	  not have ACPI.
2625
2626	  There's no public spec for this chipset, and this functionality
2627	  is known to be incomplete.
2628
2629	  You should say N unless you know you need this.
2630
2631config ISA_BUS
2632	bool "ISA bus support on modern systems" if EXPERT
2633	help
2634	  Expose ISA bus device drivers and options available for selection and
2635	  configuration. Enable this option if your target machine has an ISA
2636	  bus. ISA is an older system, displaced by PCI and newer bus
2637	  architectures -- if your target machine is modern, it probably does
2638	  not have an ISA bus.
2639
2640	  If unsure, say N.
2641
2642# x86_64 have no ISA slots, but can have ISA-style DMA.
2643config ISA_DMA_API
2644	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2645	default y
2646	help
2647	  Enables ISA-style DMA support for devices requiring such controllers.
2648	  If unsure, say Y.
2649
2650if X86_32
2651
2652config ISA
2653	bool "ISA support"
2654	help
2655	  Find out whether you have ISA slots on your motherboard.  ISA is the
2656	  name of a bus system, i.e. the way the CPU talks to the other stuff
2657	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2658	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2659	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2660
2661config SCx200
2662	tristate "NatSemi SCx200 support"
2663	help
2664	  This provides basic support for National Semiconductor's
2665	  (now AMD's) Geode processors.  The driver probes for the
2666	  PCI-IDs of several on-chip devices, so its a good dependency
2667	  for other scx200_* drivers.
2668
2669	  If compiled as a module, the driver is named scx200.
2670
2671config SCx200HR_TIMER
2672	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2673	depends on SCx200
2674	default y
2675	help
2676	  This driver provides a clocksource built upon the on-chip
2677	  27MHz high-resolution timer.  Its also a workaround for
2678	  NSC Geode SC-1100's buggy TSC, which loses time when the
2679	  processor goes idle (as is done by the scheduler).  The
2680	  other workaround is idle=poll boot option.
2681
2682config OLPC
2683	bool "One Laptop Per Child support"
2684	depends on !X86_PAE
2685	select GPIOLIB
2686	select OF
2687	select OF_PROMTREE
2688	select IRQ_DOMAIN
2689	select OLPC_EC
2690	help
2691	  Add support for detecting the unique features of the OLPC
2692	  XO hardware.
2693
2694config OLPC_XO1_PM
2695	bool "OLPC XO-1 Power Management"
2696	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2697	help
2698	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2699
2700config OLPC_XO1_RTC
2701	bool "OLPC XO-1 Real Time Clock"
2702	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2703	help
2704	  Add support for the XO-1 real time clock, which can be used as a
2705	  programmable wakeup source.
2706
2707config OLPC_XO1_SCI
2708	bool "OLPC XO-1 SCI extras"
2709	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2710	depends on INPUT=y
2711	select POWER_SUPPLY
2712	help
2713	  Add support for SCI-based features of the OLPC XO-1 laptop:
2714	   - EC-driven system wakeups
2715	   - Power button
2716	   - Ebook switch
2717	   - Lid switch
2718	   - AC adapter status updates
2719	   - Battery status updates
2720
2721config OLPC_XO15_SCI
2722	bool "OLPC XO-1.5 SCI extras"
2723	depends on OLPC && ACPI
2724	select POWER_SUPPLY
2725	help
2726	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2727	   - EC-driven system wakeups
2728	   - AC adapter status updates
2729	   - Battery status updates
2730
2731config ALIX
2732	bool "PCEngines ALIX System Support (LED setup)"
2733	select GPIOLIB
2734	help
2735	  This option enables system support for the PCEngines ALIX.
2736	  At present this just sets up LEDs for GPIO control on
2737	  ALIX2/3/6 boards.  However, other system specific setup should
2738	  get added here.
2739
2740	  Note: You must still enable the drivers for GPIO and LED support
2741	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2742
2743	  Note: You have to set alix.force=1 for boards with Award BIOS.
2744
2745config NET5501
2746	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2747	select GPIOLIB
2748	help
2749	  This option enables system support for the Soekris Engineering net5501.
2750
2751config GEOS
2752	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2753	select GPIOLIB
2754	depends on DMI
2755	help
2756	  This option enables system support for the Traverse Technologies GEOS.
2757
2758config TS5500
2759	bool "Technologic Systems TS-5500 platform support"
2760	depends on MELAN
2761	select CHECK_SIGNATURE
2762	select NEW_LEDS
2763	select LEDS_CLASS
2764	help
2765	  This option enables system support for the Technologic Systems TS-5500.
2766
2767endif # X86_32
2768
2769config AMD_NB
2770	def_bool y
2771	depends on CPU_SUP_AMD && PCI
2772
2773endmenu
2774
2775
2776menu "Binary Emulations"
2777
2778config IA32_EMULATION
2779	bool "IA32 Emulation"
2780	depends on X86_64
2781	select ARCH_WANT_OLD_COMPAT_IPC
2782	select BINFMT_ELF
2783	select COMPAT_OLD_SIGACTION
2784	help
2785	  Include code to run legacy 32-bit programs under a
2786	  64-bit kernel. You should likely turn this on, unless you're
2787	  100% sure that you don't have any 32-bit programs left.
2788
2789config IA32_AOUT
2790	tristate "IA32 a.out support"
2791	depends on IA32_EMULATION
2792	depends on BROKEN
2793	help
2794	  Support old a.out binaries in the 32bit emulation.
2795
2796config X86_X32
2797	bool "x32 ABI for 64-bit mode"
2798	depends on X86_64
2799	help
2800	  Include code to run binaries for the x32 native 32-bit ABI
2801	  for 64-bit processors.  An x32 process gets access to the
2802	  full 64-bit register file and wide data path while leaving
2803	  pointers at 32 bits for smaller memory footprint.
2804
2805	  You will need a recent binutils (2.22 or later) with
2806	  elf32_x86_64 support enabled to compile a kernel with this
2807	  option set.
2808
2809config COMPAT_32
2810	def_bool y
2811	depends on IA32_EMULATION || X86_32
2812	select HAVE_UID16
2813	select OLD_SIGSUSPEND3
2814
2815config COMPAT
2816	def_bool y
2817	depends on IA32_EMULATION || X86_X32
2818
2819if COMPAT
2820config COMPAT_FOR_U64_ALIGNMENT
2821	def_bool y
2822
2823config SYSVIPC_COMPAT
2824	def_bool y
2825	depends on SYSVIPC
2826endif
2827
2828endmenu
2829
2830
2831config HAVE_ATOMIC_IOMAP
2832	def_bool y
2833	depends on X86_32
2834
2835source "drivers/firmware/Kconfig"
2836
2837source "arch/x86/kvm/Kconfig"
2838
2839source "arch/x86/Kconfig.assembler"
2840