xref: /OK3568_Linux_fs/kernel/arch/x86/Kconfig (revision 4882a59341e53eb6f0b4789bf948001014eff981)
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 HAVE_DEBUG_STACKOVERFLOW
18	select MODULES_USE_ELF_REL
19	select OLD_SIGACTION
20	select GENERIC_VDSO_32
21	select ARCH_SPLIT_ARG64
22
23config X86_64
24	def_bool y
25	depends on 64BIT
26	# Options that are inherently 64-bit kernel only:
27	select ARCH_HAS_GIGANTIC_PAGE
28	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
29	select ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT
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
36config FORCE_DYNAMIC_FTRACE
37	def_bool y
38	depends on X86_32
39	depends on FUNCTION_TRACER
40	select DYNAMIC_FTRACE
41	help
42	 We keep the static function tracing (!DYNAMIC_FTRACE) around
43	 in order to test the non static function tracing in the
44	 generic code, as other architectures still use it. But we
45	 only need to keep it around for x86_64. No need to keep it
46	 for x86_32. For x86_32, force DYNAMIC_FTRACE.
47#
48# Arch settings
49#
50# ( Note that options that are marked 'if X86_64' could in principle be
51#   ported to 32-bit as well. )
52#
53config X86
54	def_bool y
55	#
56	# Note: keep this list sorted alphabetically
57	#
58	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
59	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
60	select ARCH_32BIT_OFF_T			if X86_32
61	select ARCH_CLOCKSOURCE_INIT
62	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
63	select ARCH_HAS_DEBUG_VIRTUAL
64	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
65	select ARCH_HAS_DEVMEM_IS_ALLOWED
66	select ARCH_HAS_EARLY_DEBUG		if KGDB
67	select ARCH_HAS_ELF_RANDOMIZE
68	select ARCH_HAS_FAST_MULTIPLIER
69	select ARCH_HAS_FILTER_PGPROT
70	select ARCH_HAS_FORTIFY_SOURCE
71	select ARCH_HAS_GCOV_PROFILE_ALL
72	select ARCH_HAS_KCOV			if X86_64 && STACK_VALIDATION
73	select ARCH_HAS_MEM_ENCRYPT
74	select ARCH_HAS_MEMBARRIER_SYNC_CORE
75	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
76	select ARCH_HAS_PMEM_API		if X86_64
77	select ARCH_HAS_PTE_DEVMAP		if X86_64
78	select ARCH_HAS_PTE_SPECIAL
79	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
80	select ARCH_HAS_COPY_MC			if X86_64
81	select ARCH_HAS_SET_MEMORY
82	select ARCH_HAS_SET_DIRECT_MAP
83	select ARCH_HAS_STRICT_KERNEL_RWX
84	select ARCH_HAS_STRICT_MODULE_RWX
85	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
86	select ARCH_HAS_SYSCALL_WRAPPER
87	select ARCH_HAS_UBSAN_SANITIZE_ALL
88	select ARCH_HAS_DEBUG_WX
89	select ARCH_HAVE_NMI_SAFE_CMPXCHG
90	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
91	select ARCH_MIGHT_HAVE_PC_PARPORT
92	select ARCH_MIGHT_HAVE_PC_SERIO
93	select ARCH_STACKWALK
94	select ARCH_SUPPORTS_ACPI
95	select ARCH_SUPPORTS_ATOMIC_RMW
96	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
97	select ARCH_SUPPORTS_LTO_CLANG		if X86_64
98	select ARCH_SUPPORTS_LTO_CLANG_THIN	if X86_64
99	select ARCH_USE_BUILTIN_BSWAP
100	select ARCH_USE_QUEUED_RWLOCKS
101	select ARCH_USE_QUEUED_SPINLOCKS
102	select ARCH_USE_SYM_ANNOTATIONS
103	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
104	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
105	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
106	select ARCH_WANT_HUGE_PMD_SHARE
107	select ARCH_WANT_LD_ORPHAN_WARN
108	select ARCH_WANTS_THP_SWAP		if X86_64
109	select BUILDTIME_TABLE_SORT
110	select CLKEVT_I8253
111	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
112	select CLOCKSOURCE_WATCHDOG
113	select DCACHE_WORD_ACCESS
114	select EDAC_ATOMIC_SCRUB
115	select EDAC_SUPPORT
116	select GENERIC_CLOCKEVENTS
117	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
118	select GENERIC_CLOCKEVENTS_MIN_ADJUST
119	select GENERIC_CMOS_UPDATE
120	select GENERIC_CPU_AUTOPROBE
121	select GENERIC_CPU_VULNERABILITIES
122	select GENERIC_EARLY_IOREMAP
123	select GENERIC_ENTRY
124	select GENERIC_FIND_FIRST_BIT
125	select GENERIC_IOMAP
126	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
127	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
128	select GENERIC_IRQ_MIGRATION		if SMP
129	select GENERIC_IRQ_PROBE
130	select GENERIC_IRQ_RESERVATION_MODE
131	select GENERIC_IRQ_SHOW
132	select GENERIC_PENDING_IRQ		if SMP
133	select GENERIC_PTDUMP
134	select GENERIC_SMP_IDLE_THREAD
135	select GENERIC_STRNCPY_FROM_USER
136	select GENERIC_STRNLEN_USER
137	select GENERIC_TIME_VSYSCALL
138	select GENERIC_GETTIMEOFDAY
139	select GENERIC_VDSO_TIME_NS
140	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
141	select HARDIRQS_SW_RESEND
142	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
143	select HAVE_ACPI_APEI			if ACPI
144	select HAVE_ACPI_APEI_NMI		if ACPI
145	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
146	select HAVE_ARCH_AUDITSYSCALL
147	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
148	select HAVE_ARCH_JUMP_LABEL
149	select HAVE_ARCH_JUMP_LABEL_RELATIVE
150	select HAVE_ARCH_KASAN			if X86_64
151	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
152	select HAVE_ARCH_KFENCE
153	select HAVE_ARCH_KGDB
154	select HAVE_ARCH_MMAP_RND_BITS		if MMU
155	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
156	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
157	select HAVE_ARCH_PREL32_RELOCATIONS
158	select HAVE_ARCH_SECCOMP_FILTER
159	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
160	select HAVE_ARCH_STACKLEAK
161	select HAVE_ARCH_TRACEHOOK
162	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
163	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
164	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
165	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
166	select HAVE_ARCH_VMAP_STACK		if X86_64
167	select HAVE_ARCH_WITHIN_STACK_FRAMES
168	select HAVE_ASM_MODVERSIONS
169	select HAVE_CMPXCHG_DOUBLE
170	select HAVE_CMPXCHG_LOCAL
171	select HAVE_CONTEXT_TRACKING		if X86_64
172	select HAVE_C_RECORDMCOUNT
173	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
174	select HAVE_DEBUG_KMEMLEAK
175	select HAVE_DMA_CONTIGUOUS
176	select HAVE_DYNAMIC_FTRACE
177	select HAVE_DYNAMIC_FTRACE_WITH_REGS
178	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
179	select HAVE_EBPF_JIT
180	select HAVE_EFFICIENT_UNALIGNED_ACCESS
181	select HAVE_EISA
182	select HAVE_EXIT_THREAD
183	select HAVE_FAST_GUP
184	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
185	select HAVE_FTRACE_MCOUNT_RECORD
186	select HAVE_FUNCTION_GRAPH_TRACER
187	select HAVE_FUNCTION_TRACER
188	select HAVE_GCC_PLUGINS
189	select HAVE_HW_BREAKPOINT
190	select HAVE_IDE
191	select HAVE_IOREMAP_PROT
192	select HAVE_IRQ_TIME_ACCOUNTING
193	select HAVE_KERNEL_BZIP2
194	select HAVE_KERNEL_GZIP
195	select HAVE_KERNEL_LZ4
196	select HAVE_KERNEL_LZMA
197	select HAVE_KERNEL_LZO
198	select HAVE_KERNEL_XZ
199	select HAVE_KERNEL_ZSTD
200	select HAVE_KPROBES
201	select HAVE_KPROBES_ON_FTRACE
202	select HAVE_FUNCTION_ERROR_INJECTION
203	select HAVE_KRETPROBES
204	select HAVE_KVM
205	select HAVE_LIVEPATCH			if X86_64
206	select HAVE_MIXED_BREAKPOINTS_REGS
207	select HAVE_MOD_ARCH_SPECIFIC
208	select HAVE_MOVE_PMD
209	select HAVE_MOVE_PUD
210	select HAVE_NMI
211	select HAVE_OPROFILE
212	select HAVE_OPTPROBES
213	select HAVE_PCSPKR_PLATFORM
214	select HAVE_PERF_EVENTS
215	select HAVE_PERF_EVENTS_NMI
216	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
217	select HAVE_PCI
218	select HAVE_PERF_REGS
219	select HAVE_PERF_USER_STACK_DUMP
220	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
221	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
222	select HAVE_REGS_AND_STACK_ACCESS_API
223	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
224	select HAVE_FUNCTION_ARG_ACCESS_API
225	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
226	select HAVE_STACK_VALIDATION		if X86_64
227	select HAVE_STATIC_CALL
228	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
229	select HAVE_RSEQ
230	select HAVE_SYSCALL_TRACEPOINTS
231	select HAVE_UNSTABLE_SCHED_CLOCK
232	select HAVE_USER_RETURN_NOTIFIER
233	select HAVE_GENERIC_VDSO
234	select HOTPLUG_SMT			if SMP
235	select IRQ_FORCED_THREADING
236	select NEED_SG_DMA_LENGTH
237	select PCI_DOMAINS			if PCI
238	select PCI_LOCKLESS_CONFIG		if PCI
239	select PERF_EVENTS
240	select RTC_LIB
241	select RTC_MC146818_LIB
242	select SPARSE_IRQ
243	select SRCU
244	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
245	select SYSCTL_EXCEPTION_TRACE
246	select THREAD_INFO_IN_TASK
247	select USER_STACKTRACE_SUPPORT
248	select VIRT_TO_BUS
249	select HAVE_ARCH_KCSAN			if X86_64
250	select X86_FEATURE_NAMES		if PROC_FS
251	select PROC_PID_ARCH_STATUS		if PROC_FS
252	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
253
254config INSTRUCTION_DECODER
255	def_bool y
256	depends on KPROBES || PERF_EVENTS || UPROBES
257
258config OUTPUT_FORMAT
259	string
260	default "elf32-i386" if X86_32
261	default "elf64-x86-64" if X86_64
262
263config LOCKDEP_SUPPORT
264	def_bool y
265
266config STACKTRACE_SUPPORT
267	def_bool y
268
269config MMU
270	def_bool y
271
272config ARCH_MMAP_RND_BITS_MIN
273	default 28 if 64BIT
274	default 8
275
276config ARCH_MMAP_RND_BITS_MAX
277	default 32 if 64BIT
278	default 16
279
280config ARCH_MMAP_RND_COMPAT_BITS_MIN
281	default 8
282
283config ARCH_MMAP_RND_COMPAT_BITS_MAX
284	default 16
285
286config SBUS
287	bool
288
289config GENERIC_ISA_DMA
290	def_bool y
291	depends on ISA_DMA_API
292
293config GENERIC_BUG
294	def_bool y
295	depends on BUG
296	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
297
298config GENERIC_BUG_RELATIVE_POINTERS
299	bool
300
301config ARCH_MAY_HAVE_PC_FDC
302	def_bool y
303	depends on ISA_DMA_API
304
305config GENERIC_CALIBRATE_DELAY
306	def_bool y
307
308config ARCH_HAS_CPU_RELAX
309	def_bool y
310
311config ARCH_HAS_CACHE_LINE_SIZE
312	def_bool y
313
314config ARCH_HAS_FILTER_PGPROT
315	def_bool y
316
317config HAVE_SETUP_PER_CPU_AREA
318	def_bool y
319
320config NEED_PER_CPU_EMBED_FIRST_CHUNK
321	def_bool y
322
323config NEED_PER_CPU_PAGE_FIRST_CHUNK
324	def_bool y
325
326config ARCH_HIBERNATION_POSSIBLE
327	def_bool y
328
329config ARCH_SUSPEND_POSSIBLE
330	def_bool y
331
332config ARCH_WANT_GENERAL_HUGETLB
333	def_bool y
334
335config ZONE_DMA32
336	def_bool y if X86_64
337
338config AUDIT_ARCH
339	def_bool y if X86_64
340
341config ARCH_SUPPORTS_DEBUG_PAGEALLOC
342	def_bool y
343
344config KASAN_SHADOW_OFFSET
345	hex
346	depends on KASAN
347	default 0xdffffc0000000000
348
349config HAVE_INTEL_TXT
350	def_bool y
351	depends on INTEL_IOMMU && ACPI
352
353config X86_32_SMP
354	def_bool y
355	depends on X86_32 && SMP
356
357config X86_64_SMP
358	def_bool y
359	depends on X86_64 && SMP
360
361config X86_32_LAZY_GS
362	def_bool y
363	depends on X86_32 && !STACKPROTECTOR
364
365config ARCH_SUPPORTS_UPROBES
366	def_bool y
367
368config FIX_EARLYCON_MEM
369	def_bool y
370
371config DYNAMIC_PHYSICAL_MASK
372	bool
373
374config PGTABLE_LEVELS
375	int
376	default 5 if X86_5LEVEL
377	default 4 if X86_64
378	default 3 if X86_PAE
379	default 2
380
381config CC_HAS_SANE_STACKPROTECTOR
382	bool
383	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
384	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
385	help
386	   We have to make sure stack protector is unconditionally disabled if
387	   the compiler produces broken code.
388
389menu "Processor type and features"
390
391config ZONE_DMA
392	bool "DMA memory allocation support" if EXPERT
393	default y
394	help
395	  DMA memory allocation support allows devices with less than 32-bit
396	  addressing to allocate within the first 16MB of address space.
397	  Disable if no such devices will be used.
398
399	  If unsure, say Y.
400
401config SMP
402	bool "Symmetric multi-processing support"
403	help
404	  This enables support for systems with more than one CPU. If you have
405	  a system with only one CPU, say N. If you have a system with more
406	  than one CPU, say Y.
407
408	  If you say N here, the kernel will run on uni- and multiprocessor
409	  machines, but will use only one CPU of a multiprocessor machine. If
410	  you say Y here, the kernel will run on many, but not all,
411	  uniprocessor machines. On a uniprocessor machine, the kernel
412	  will run faster if you say N here.
413
414	  Note that if you say Y here and choose architecture "586" or
415	  "Pentium" under "Processor family", the kernel will not work on 486
416	  architectures. Similarly, multiprocessor kernels for the "PPro"
417	  architecture may not work on all Pentium based boards.
418
419	  People using multiprocessor machines who say Y here should also say
420	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
421	  Management" code will be disabled if you say Y here.
422
423	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
424	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
425	  <http://www.tldp.org/docs.html#howto>.
426
427	  If you don't know what to do here, say N.
428
429config X86_FEATURE_NAMES
430	bool "Processor feature human-readable names" if EMBEDDED
431	default y
432	help
433	  This option compiles in a table of x86 feature bits and corresponding
434	  names.  This is required to support /proc/cpuinfo and a few kernel
435	  messages.  You can disable this to save space, at the expense of
436	  making those few kernel messages show numeric feature bits instead.
437
438	  If in doubt, say Y.
439
440config X86_X2APIC
441	bool "Support x2apic"
442	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
443	help
444	  This enables x2apic support on CPUs that have this feature.
445
446	  This allows 32-bit apic IDs (so it can support very large systems),
447	  and accesses the local apic via MSRs not via mmio.
448
449	  If you don't know what to do here, say N.
450
451config X86_MPPARSE
452	bool "Enable MPS table" if ACPI || SFI
453	default y
454	depends on X86_LOCAL_APIC
455	help
456	  For old smp systems that do not have proper acpi support. Newer systems
457	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
458
459config GOLDFISH
460	def_bool y
461	depends on X86_GOLDFISH
462
463config X86_CPU_RESCTRL
464	bool "x86 CPU resource control support"
465	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
466	select KERNFS
467	select PROC_CPU_RESCTRL		if PROC_FS
468	help
469	  Enable x86 CPU resource control support.
470
471	  Provide support for the allocation and monitoring of system resources
472	  usage by the CPU.
473
474	  Intel calls this Intel Resource Director Technology
475	  (Intel(R) RDT). More information about RDT can be found in the
476	  Intel x86 Architecture Software Developer Manual.
477
478	  AMD calls this AMD Platform Quality of Service (AMD QoS).
479	  More information about AMD QoS can be found in the AMD64 Technology
480	  Platform Quality of Service Extensions manual.
481
482	  Say N if unsure.
483
484if X86_32
485config X86_BIGSMP
486	bool "Support for big SMP systems with more than 8 CPUs"
487	depends on SMP
488	help
489	  This option is needed for the systems that have more than 8 CPUs.
490
491config X86_EXTENDED_PLATFORM
492	bool "Support for extended (non-PC) x86 platforms"
493	default y
494	help
495	  If you disable this option then the kernel will only support
496	  standard PC platforms. (which covers the vast majority of
497	  systems out there.)
498
499	  If you enable this option then you'll be able to select support
500	  for the following (non-PC) 32 bit x86 platforms:
501		Goldfish (Android emulator)
502		AMD Elan
503		RDC R-321x SoC
504		SGI 320/540 (Visual Workstation)
505		STA2X11-based (e.g. Northville)
506		Moorestown MID devices
507
508	  If you have one of these systems, or if you want to build a
509	  generic distribution kernel, say Y here - otherwise say N.
510endif
511
512if X86_64
513config X86_EXTENDED_PLATFORM
514	bool "Support for extended (non-PC) x86 platforms"
515	default y
516	help
517	  If you disable this option then the kernel will only support
518	  standard PC platforms. (which covers the vast majority of
519	  systems out there.)
520
521	  If you enable this option then you'll be able to select support
522	  for the following (non-PC) 64 bit x86 platforms:
523		Numascale NumaChip
524		ScaleMP vSMP
525		SGI Ultraviolet
526
527	  If you have one of these systems, or if you want to build a
528	  generic distribution kernel, say Y here - otherwise say N.
529endif
530# This is an alphabetically sorted list of 64 bit extended platforms
531# Please maintain the alphabetic order if and when there are additions
532config X86_NUMACHIP
533	bool "Numascale NumaChip"
534	depends on X86_64
535	depends on X86_EXTENDED_PLATFORM
536	depends on NUMA
537	depends on SMP
538	depends on X86_X2APIC
539	depends on PCI_MMCONFIG
540	help
541	  Adds support for Numascale NumaChip large-SMP systems. Needed to
542	  enable more than ~168 cores.
543	  If you don't have one of these, you should say N here.
544
545config X86_VSMP
546	bool "ScaleMP vSMP"
547	select HYPERVISOR_GUEST
548	select PARAVIRT
549	depends on X86_64 && PCI
550	depends on X86_EXTENDED_PLATFORM
551	depends on SMP
552	help
553	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
554	  supposed to run on these EM64T-based machines.  Only choose this option
555	  if you have one of these machines.
556
557config X86_UV
558	bool "SGI Ultraviolet"
559	depends on X86_64
560	depends on X86_EXTENDED_PLATFORM
561	depends on NUMA
562	depends on EFI
563	depends on KEXEC_CORE
564	depends on X86_X2APIC
565	depends on PCI
566	help
567	  This option is needed in order to support SGI Ultraviolet systems.
568	  If you don't have one of these, you should say N here.
569
570# Following is an alphabetically sorted list of 32 bit extended platforms
571# Please maintain the alphabetic order if and when there are additions
572
573config X86_GOLDFISH
574	bool "Goldfish (Virtual Platform)"
575	depends on X86_EXTENDED_PLATFORM
576	help
577	 Enable support for the Goldfish virtual platform used primarily
578	 for Android development. Unless you are building for the Android
579	 Goldfish emulator say N here.
580
581config X86_INTEL_CE
582	bool "CE4100 TV platform"
583	depends on PCI
584	depends on PCI_GODIRECT
585	depends on X86_IO_APIC
586	depends on X86_32
587	depends on X86_EXTENDED_PLATFORM
588	select X86_REBOOTFIXUPS
589	select OF
590	select OF_EARLY_FLATTREE
591	help
592	  Select for the Intel CE media processor (CE4100) SOC.
593	  This option compiles in support for the CE4100 SOC for settop
594	  boxes and media devices.
595
596config X86_INTEL_MID
597	bool "Intel MID platform support"
598	depends on X86_EXTENDED_PLATFORM
599	depends on X86_PLATFORM_DEVICES
600	depends on PCI
601	depends on X86_64 || (PCI_GOANY && X86_32)
602	depends on X86_IO_APIC
603	select SFI
604	select I2C
605	select DW_APB_TIMER
606	select APB_TIMER
607	select INTEL_SCU_PCI
608	select MFD_INTEL_MSIC
609	help
610	  Select to build a kernel capable of supporting Intel MID (Mobile
611	  Internet Device) platform systems which do not have the PCI legacy
612	  interfaces. If you are building for a PC class system say N here.
613
614	  Intel MID platforms are based on an Intel processor and chipset which
615	  consume less power than most of the x86 derivatives.
616
617config X86_INTEL_QUARK
618	bool "Intel Quark platform support"
619	depends on X86_32
620	depends on X86_EXTENDED_PLATFORM
621	depends on X86_PLATFORM_DEVICES
622	depends on X86_TSC
623	depends on PCI
624	depends on PCI_GOANY
625	depends on X86_IO_APIC
626	select IOSF_MBI
627	select INTEL_IMR
628	select COMMON_CLK
629	help
630	  Select to include support for Quark X1000 SoC.
631	  Say Y here if you have a Quark based system such as the Arduino
632	  compatible Intel Galileo.
633
634config X86_INTEL_LPSS
635	bool "Intel Low Power Subsystem Support"
636	depends on X86 && ACPI && PCI
637	select COMMON_CLK
638	select PINCTRL
639	select IOSF_MBI
640	help
641	  Select to build support for Intel Low Power Subsystem such as
642	  found on Intel Lynxpoint PCH. Selecting this option enables
643	  things like clock tree (common clock framework) and pincontrol
644	  which are needed by the LPSS peripheral drivers.
645
646config X86_AMD_PLATFORM_DEVICE
647	bool "AMD ACPI2Platform devices support"
648	depends on ACPI
649	select COMMON_CLK
650	select PINCTRL
651	help
652	  Select to interpret AMD specific ACPI device to platform device
653	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
654	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
655	  implemented under PINCTRL subsystem.
656
657config IOSF_MBI
658	tristate "Intel SoC IOSF Sideband support for SoC platforms"
659	depends on PCI
660	help
661	  This option enables sideband register access support for Intel SoC
662	  platforms. On these platforms the IOSF sideband is used in lieu of
663	  MSR's for some register accesses, mostly but not limited to thermal
664	  and power. Drivers may query the availability of this device to
665	  determine if they need the sideband in order to work on these
666	  platforms. The sideband is available on the following SoC products.
667	  This list is not meant to be exclusive.
668	   - BayTrail
669	   - Braswell
670	   - Quark
671
672	  You should say Y if you are running a kernel on one of these SoC's.
673
674config IOSF_MBI_DEBUG
675	bool "Enable IOSF sideband access through debugfs"
676	depends on IOSF_MBI && DEBUG_FS
677	help
678	  Select this option to expose the IOSF sideband access registers (MCR,
679	  MDR, MCRX) through debugfs to write and read register information from
680	  different units on the SoC. This is most useful for obtaining device
681	  state information for debug and analysis. As this is a general access
682	  mechanism, users of this option would have specific knowledge of the
683	  device they want to access.
684
685	  If you don't require the option or are in doubt, say N.
686
687config X86_RDC321X
688	bool "RDC R-321x SoC"
689	depends on X86_32
690	depends on X86_EXTENDED_PLATFORM
691	select M486
692	select X86_REBOOTFIXUPS
693	help
694	  This option is needed for RDC R-321x system-on-chip, also known
695	  as R-8610-(G).
696	  If you don't have one of these chips, you should say N here.
697
698config X86_32_NON_STANDARD
699	bool "Support non-standard 32-bit SMP architectures"
700	depends on X86_32 && SMP
701	depends on X86_EXTENDED_PLATFORM
702	help
703	  This option compiles in the bigsmp and STA2X11 default
704	  subarchitectures.  It is intended for a generic binary
705	  kernel. If you select them all, kernel will probe it one by
706	  one and will fallback to default.
707
708# Alphabetically sorted list of Non standard 32 bit platforms
709
710config X86_SUPPORTS_MEMORY_FAILURE
711	def_bool y
712	# MCE code calls memory_failure():
713	depends on X86_MCE
714	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
715	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
716	depends on X86_64 || !SPARSEMEM
717	select ARCH_SUPPORTS_MEMORY_FAILURE
718
719config STA2X11
720	bool "STA2X11 Companion Chip Support"
721	depends on X86_32_NON_STANDARD && PCI
722	select SWIOTLB
723	select MFD_STA2X11
724	select GPIOLIB
725	help
726	  This adds support for boards based on the STA2X11 IO-Hub,
727	  a.k.a. "ConneXt". The chip is used in place of the standard
728	  PC chipset, so all "standard" peripherals are missing. If this
729	  option is selected the kernel will still be able to boot on
730	  standard PC machines.
731
732config X86_32_IRIS
733	tristate "Eurobraille/Iris poweroff module"
734	depends on X86_32
735	help
736	  The Iris machines from EuroBraille do not have APM or ACPI support
737	  to shut themselves down properly.  A special I/O sequence is
738	  needed to do so, which is what this module does at
739	  kernel shutdown.
740
741	  This is only for Iris machines from EuroBraille.
742
743	  If unused, say N.
744
745config SCHED_OMIT_FRAME_POINTER
746	def_bool y
747	prompt "Single-depth WCHAN output"
748	depends on X86
749	help
750	  Calculate simpler /proc/<PID>/wchan values. If this option
751	  is disabled then wchan values will recurse back to the
752	  caller function. This provides more accurate wchan values,
753	  at the expense of slightly more scheduling overhead.
754
755	  If in doubt, say "Y".
756
757menuconfig HYPERVISOR_GUEST
758	bool "Linux guest support"
759	help
760	  Say Y here to enable options for running Linux under various hyper-
761	  visors. This option enables basic hypervisor detection and platform
762	  setup.
763
764	  If you say N, all options in this submenu will be skipped and
765	  disabled, and Linux guest support won't be built in.
766
767if HYPERVISOR_GUEST
768
769config PARAVIRT
770	bool "Enable paravirtualization code"
771	help
772	  This changes the kernel so it can modify itself when it is run
773	  under a hypervisor, potentially improving performance significantly
774	  over full virtualization.  However, when run without a hypervisor
775	  the kernel is theoretically slower and slightly larger.
776
777config PARAVIRT_XXL
778	bool
779
780config PARAVIRT_DEBUG
781	bool "paravirt-ops debugging"
782	depends on PARAVIRT && DEBUG_KERNEL
783	help
784	  Enable to debug paravirt_ops internals.  Specifically, BUG if
785	  a paravirt_op is missing when it is called.
786
787config PARAVIRT_SPINLOCKS
788	bool "Paravirtualization layer for spinlocks"
789	depends on PARAVIRT && SMP
790	help
791	  Paravirtualized spinlocks allow a pvops backend to replace the
792	  spinlock implementation with something virtualization-friendly
793	  (for example, block the virtual CPU rather than spinning).
794
795	  It has a minimal impact on native kernels and gives a nice performance
796	  benefit on paravirtualized KVM / Xen kernels.
797
798	  If you are unsure how to answer this question, answer Y.
799
800config X86_HV_CALLBACK_VECTOR
801	def_bool n
802
803source "arch/x86/xen/Kconfig"
804
805config KVM_GUEST
806	bool "KVM Guest support (including kvmclock)"
807	depends on PARAVIRT
808	select PARAVIRT_CLOCK
809	select ARCH_CPUIDLE_HALTPOLL
810	select X86_HV_CALLBACK_VECTOR
811	default y
812	help
813	  This option enables various optimizations for running under the KVM
814	  hypervisor. It includes a paravirtualized clock, so that instead
815	  of relying on a PIT (or probably other) emulation by the
816	  underlying device model, the host provides the guest with
817	  timing infrastructure such as time of day, and system time
818
819config ARCH_CPUIDLE_HALTPOLL
820	def_bool n
821	prompt "Disable host haltpoll when loading haltpoll driver"
822	help
823	  If virtualized under KVM, disable host haltpoll.
824
825config PVH
826	bool "Support for running PVH guests"
827	help
828	  This option enables the PVH entry point for guest virtual machines
829	  as specified in the x86/HVM direct boot ABI.
830
831config PARAVIRT_TIME_ACCOUNTING
832	bool "Paravirtual steal time accounting"
833	depends on PARAVIRT
834	help
835	  Select this option to enable fine granularity task steal time
836	  accounting. Time spent executing other tasks in parallel with
837	  the current vCPU is discounted from the vCPU power. To account for
838	  that, there can be a small performance impact.
839
840	  If in doubt, say N here.
841
842config PARAVIRT_CLOCK
843	bool
844
845config JAILHOUSE_GUEST
846	bool "Jailhouse non-root cell support"
847	depends on X86_64 && PCI
848	select X86_PM_TIMER
849	help
850	  This option allows to run Linux as guest in a Jailhouse non-root
851	  cell. You can leave this option disabled if you only want to start
852	  Jailhouse and run Linux afterwards in the root cell.
853
854config ACRN_GUEST
855	bool "ACRN Guest support"
856	depends on X86_64
857	select X86_HV_CALLBACK_VECTOR
858	help
859	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
860	  a flexible, lightweight reference open-source hypervisor, built with
861	  real-time and safety-criticality in mind. It is built for embedded
862	  IOT with small footprint and real-time features. More details can be
863	  found in https://projectacrn.org/.
864
865endif #HYPERVISOR_GUEST
866
867source "arch/x86/Kconfig.cpu"
868
869config HPET_TIMER
870	def_bool X86_64
871	prompt "HPET Timer Support" if X86_32
872	help
873	  Use the IA-PC HPET (High Precision Event Timer) to manage
874	  time in preference to the PIT and RTC, if a HPET is
875	  present.
876	  HPET is the next generation timer replacing legacy 8254s.
877	  The HPET provides a stable time base on SMP
878	  systems, unlike the TSC, but it is more expensive to access,
879	  as it is off-chip.  The interface used is documented
880	  in the HPET spec, revision 1.
881
882	  You can safely choose Y here.  However, HPET will only be
883	  activated if the platform and the BIOS support this feature.
884	  Otherwise the 8254 will be used for timing services.
885
886	  Choose N to continue using the legacy 8254 timer.
887
888config HPET_EMULATE_RTC
889	def_bool y
890	depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
891
892config APB_TIMER
893	def_bool y if X86_INTEL_MID
894	prompt "Intel MID APB Timer Support" if X86_INTEL_MID
895	select DW_APB_TIMER
896	depends on X86_INTEL_MID && SFI
897	help
898	 APB timer is the replacement for 8254, HPET on X86 MID platforms.
899	 The APBT provides a stable time base on SMP
900	 systems, unlike the TSC, but it is more expensive to access,
901	 as it is off-chip. APB timers are always running regardless of CPU
902	 C states, they are used as per CPU clockevent device when possible.
903
904# Mark as expert because too many people got it wrong.
905# The code disables itself when not needed.
906config DMI
907	default y
908	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
909	bool "Enable DMI scanning" if EXPERT
910	help
911	  Enabled scanning of DMI to identify machine quirks. Say Y
912	  here unless you have verified that your setup is not
913	  affected by entries in the DMI blacklist. Required by PNP
914	  BIOS code.
915
916config GART_IOMMU
917	bool "Old AMD GART IOMMU support"
918	select DMA_OPS
919	select IOMMU_HELPER
920	select SWIOTLB
921	depends on X86_64 && PCI && AMD_NB
922	help
923	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
924	  GART based hardware IOMMUs.
925
926	  The GART supports full DMA access for devices with 32-bit access
927	  limitations, on systems with more than 3 GB. This is usually needed
928	  for USB, sound, many IDE/SATA chipsets and some other devices.
929
930	  Newer systems typically have a modern AMD IOMMU, supported via
931	  the CONFIG_AMD_IOMMU=y config option.
932
933	  In normal configurations this driver is only active when needed:
934	  there's more than 3 GB of memory and the system contains a
935	  32-bit limited device.
936
937	  If unsure, say Y.
938
939config MAXSMP
940	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
941	depends on X86_64 && SMP && DEBUG_KERNEL
942	select CPUMASK_OFFSTACK
943	help
944	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
945	  If unsure, say N.
946
947#
948# The maximum number of CPUs supported:
949#
950# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
951# and which can be configured interactively in the
952# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
953#
954# The ranges are different on 32-bit and 64-bit kernels, depending on
955# hardware capabilities and scalability features of the kernel.
956#
957# ( If MAXSMP is enabled we just use the highest possible value and disable
958#   interactive configuration. )
959#
960
961config NR_CPUS_RANGE_BEGIN
962	int
963	default NR_CPUS_RANGE_END if MAXSMP
964	default    1 if !SMP
965	default    2
966
967config NR_CPUS_RANGE_END
968	int
969	depends on X86_32
970	default   64 if  SMP &&  X86_BIGSMP
971	default    8 if  SMP && !X86_BIGSMP
972	default    1 if !SMP
973
974config NR_CPUS_RANGE_END
975	int
976	depends on X86_64
977	default 8192 if  SMP && CPUMASK_OFFSTACK
978	default  512 if  SMP && !CPUMASK_OFFSTACK
979	default    1 if !SMP
980
981config NR_CPUS_DEFAULT
982	int
983	depends on X86_32
984	default   32 if  X86_BIGSMP
985	default    8 if  SMP
986	default    1 if !SMP
987
988config NR_CPUS_DEFAULT
989	int
990	depends on X86_64
991	default 8192 if  MAXSMP
992	default   64 if  SMP
993	default    1 if !SMP
994
995config NR_CPUS
996	int "Maximum number of CPUs" if SMP && !MAXSMP
997	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
998	default NR_CPUS_DEFAULT
999	help
1000	  This allows you to specify the maximum number of CPUs which this
1001	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1002	  supported value is 8192, otherwise the maximum value is 512.  The
1003	  minimum value which makes sense is 2.
1004
1005	  This is purely to save memory: each supported CPU adds about 8KB
1006	  to the kernel image.
1007
1008config SCHED_SMT
1009	def_bool y if SMP
1010
1011config SCHED_MC
1012	def_bool y
1013	prompt "Multi-core scheduler support"
1014	depends on SMP
1015	help
1016	  Multi-core scheduler support improves the CPU scheduler's decision
1017	  making when dealing with multi-core CPU chips at a cost of slightly
1018	  increased overhead in some places. If unsure say N here.
1019
1020config SCHED_MC_PRIO
1021	bool "CPU core priorities scheduler support"
1022	depends on SCHED_MC && CPU_SUP_INTEL
1023	select X86_INTEL_PSTATE
1024	select CPU_FREQ
1025	default y
1026	help
1027	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1028	  core ordering determined at manufacturing time, which allows
1029	  certain cores to reach higher turbo frequencies (when running
1030	  single threaded workloads) than others.
1031
1032	  Enabling this kernel feature teaches the scheduler about
1033	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1034	  scheduler's CPU selection logic accordingly, so that higher
1035	  overall system performance can be achieved.
1036
1037	  This feature will have no effect on CPUs without this feature.
1038
1039	  If unsure say Y here.
1040
1041config UP_LATE_INIT
1042	def_bool y
1043	depends on !SMP && X86_LOCAL_APIC
1044
1045config X86_UP_APIC
1046	bool "Local APIC support on uniprocessors" if !PCI_MSI
1047	default PCI_MSI
1048	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1049	help
1050	  A local APIC (Advanced Programmable Interrupt Controller) is an
1051	  integrated interrupt controller in the CPU. If you have a single-CPU
1052	  system which has a processor with a local APIC, you can say Y here to
1053	  enable and use it. If you say Y here even though your machine doesn't
1054	  have a local APIC, then the kernel will still run with no slowdown at
1055	  all. The local APIC supports CPU-generated self-interrupts (timer,
1056	  performance counters), and the NMI watchdog which detects hard
1057	  lockups.
1058
1059config X86_UP_IOAPIC
1060	bool "IO-APIC support on uniprocessors"
1061	depends on X86_UP_APIC
1062	help
1063	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1064	  SMP-capable replacement for PC-style interrupt controllers. Most
1065	  SMP systems and many recent uniprocessor systems have one.
1066
1067	  If you have a single-CPU system with an IO-APIC, you can say Y here
1068	  to use it. If you say Y here even though your machine doesn't have
1069	  an IO-APIC, then the kernel will still run with no slowdown at all.
1070
1071config X86_LOCAL_APIC
1072	def_bool y
1073	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1074	select IRQ_DOMAIN_HIERARCHY
1075	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1076
1077config X86_IO_APIC
1078	def_bool y
1079	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1080
1081config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1082	bool "Reroute for broken boot IRQs"
1083	depends on X86_IO_APIC
1084	help
1085	  This option enables a workaround that fixes a source of
1086	  spurious interrupts. This is recommended when threaded
1087	  interrupt handling is used on systems where the generation of
1088	  superfluous "boot interrupts" cannot be disabled.
1089
1090	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1091	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1092	  kernel does during interrupt handling). On chipsets where this
1093	  boot IRQ generation cannot be disabled, this workaround keeps
1094	  the original IRQ line masked so that only the equivalent "boot
1095	  IRQ" is delivered to the CPUs. The workaround also tells the
1096	  kernel to set up the IRQ handler on the boot IRQ line. In this
1097	  way only one interrupt is delivered to the kernel. Otherwise
1098	  the spurious second interrupt may cause the kernel to bring
1099	  down (vital) interrupt lines.
1100
1101	  Only affects "broken" chipsets. Interrupt sharing may be
1102	  increased on these systems.
1103
1104config X86_MCE
1105	bool "Machine Check / overheating reporting"
1106	select GENERIC_ALLOCATOR
1107	default y
1108	help
1109	  Machine Check support allows the processor to notify the
1110	  kernel if it detects a problem (e.g. overheating, data corruption).
1111	  The action the kernel takes depends on the severity of the problem,
1112	  ranging from warning messages to halting the machine.
1113
1114config X86_MCELOG_LEGACY
1115	bool "Support for deprecated /dev/mcelog character device"
1116	depends on X86_MCE
1117	help
1118	  Enable support for /dev/mcelog which is needed by the old mcelog
1119	  userspace logging daemon. Consider switching to the new generation
1120	  rasdaemon solution.
1121
1122config X86_MCE_INTEL
1123	def_bool y
1124	prompt "Intel MCE features"
1125	depends on X86_MCE && X86_LOCAL_APIC
1126	help
1127	   Additional support for intel specific MCE features such as
1128	   the thermal monitor.
1129
1130config X86_MCE_AMD
1131	def_bool y
1132	prompt "AMD MCE features"
1133	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1134	help
1135	   Additional support for AMD specific MCE features such as
1136	   the DRAM Error Threshold.
1137
1138config X86_ANCIENT_MCE
1139	bool "Support for old Pentium 5 / WinChip machine checks"
1140	depends on X86_32 && X86_MCE
1141	help
1142	  Include support for machine check handling on old Pentium 5 or WinChip
1143	  systems. These typically need to be enabled explicitly on the command
1144	  line.
1145
1146config X86_MCE_THRESHOLD
1147	depends on X86_MCE_AMD || X86_MCE_INTEL
1148	def_bool y
1149
1150config X86_MCE_INJECT
1151	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1152	tristate "Machine check injector support"
1153	help
1154	  Provide support for injecting machine checks for testing purposes.
1155	  If you don't know what a machine check is and you don't do kernel
1156	  QA it is safe to say n.
1157
1158config X86_THERMAL_VECTOR
1159	def_bool y
1160	depends on X86_MCE_INTEL
1161
1162source "arch/x86/events/Kconfig"
1163
1164config X86_LEGACY_VM86
1165	bool "Legacy VM86 support"
1166	depends on X86_32
1167	help
1168	  This option allows user programs to put the CPU into V8086
1169	  mode, which is an 80286-era approximation of 16-bit real mode.
1170
1171	  Some very old versions of X and/or vbetool require this option
1172	  for user mode setting.  Similarly, DOSEMU will use it if
1173	  available to accelerate real mode DOS programs.  However, any
1174	  recent version of DOSEMU, X, or vbetool should be fully
1175	  functional even without kernel VM86 support, as they will all
1176	  fall back to software emulation. Nevertheless, if you are using
1177	  a 16-bit DOS program where 16-bit performance matters, vm86
1178	  mode might be faster than emulation and you might want to
1179	  enable this option.
1180
1181	  Note that any app that works on a 64-bit kernel is unlikely to
1182	  need this option, as 64-bit kernels don't, and can't, support
1183	  V8086 mode. This option is also unrelated to 16-bit protected
1184	  mode and is not needed to run most 16-bit programs under Wine.
1185
1186	  Enabling this option increases the complexity of the kernel
1187	  and slows down exception handling a tiny bit.
1188
1189	  If unsure, say N here.
1190
1191config VM86
1192	bool
1193	default X86_LEGACY_VM86
1194
1195config X86_16BIT
1196	bool "Enable support for 16-bit segments" if EXPERT
1197	default y
1198	depends on MODIFY_LDT_SYSCALL
1199	help
1200	  This option is required by programs like Wine to run 16-bit
1201	  protected mode legacy code on x86 processors.  Disabling
1202	  this option saves about 300 bytes on i386, or around 6K text
1203	  plus 16K runtime memory on x86-64,
1204
1205config X86_ESPFIX32
1206	def_bool y
1207	depends on X86_16BIT && X86_32
1208
1209config X86_ESPFIX64
1210	def_bool y
1211	depends on X86_16BIT && X86_64
1212
1213config X86_VSYSCALL_EMULATION
1214	bool "Enable vsyscall emulation" if EXPERT
1215	default y
1216	depends on X86_64
1217	help
1218	 This enables emulation of the legacy vsyscall page.  Disabling
1219	 it is roughly equivalent to booting with vsyscall=none, except
1220	 that it will also disable the helpful warning if a program
1221	 tries to use a vsyscall.  With this option set to N, offending
1222	 programs will just segfault, citing addresses of the form
1223	 0xffffffffff600?00.
1224
1225	 This option is required by many programs built before 2013, and
1226	 care should be used even with newer programs if set to N.
1227
1228	 Disabling this option saves about 7K of kernel size and
1229	 possibly 4K of additional runtime pagetable memory.
1230
1231config X86_IOPL_IOPERM
1232	bool "IOPERM and IOPL Emulation"
1233	default y
1234	help
1235	  This enables the ioperm() and iopl() syscalls which are necessary
1236	  for legacy applications.
1237
1238	  Legacy IOPL support is an overbroad mechanism which allows user
1239	  space aside of accessing all 65536 I/O ports also to disable
1240	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1241	  capabilities and permission from potentially active security
1242	  modules.
1243
1244	  The emulation restricts the functionality of the syscall to
1245	  only allowing the full range I/O port access, but prevents the
1246	  ability to disable interrupts from user space which would be
1247	  granted if the hardware IOPL mechanism would be used.
1248
1249config TOSHIBA
1250	tristate "Toshiba Laptop support"
1251	depends on X86_32
1252	help
1253	  This adds a driver to safely access the System Management Mode of
1254	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1255	  not work on models with a Phoenix BIOS. The System Management Mode
1256	  is used to set the BIOS and power saving options on Toshiba portables.
1257
1258	  For information on utilities to make use of this driver see the
1259	  Toshiba Linux utilities web site at:
1260	  <http://www.buzzard.org.uk/toshiba/>.
1261
1262	  Say Y if you intend to run this kernel on a Toshiba portable.
1263	  Say N otherwise.
1264
1265config I8K
1266	tristate "Dell i8k legacy laptop support"
1267	depends on HWMON
1268	depends on PROC_FS
1269	select SENSORS_DELL_SMM
1270	help
1271	  This option enables legacy /proc/i8k userspace interface in hwmon
1272	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1273	  temperature and allows controlling fan speeds of Dell laptops via
1274	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1275	  it reports also power and hotkey status. For fan speed control is
1276	  needed userspace package i8kutils.
1277
1278	  Say Y if you intend to run this kernel on old Dell laptops or want to
1279	  use userspace package i8kutils.
1280	  Say N otherwise.
1281
1282config X86_REBOOTFIXUPS
1283	bool "Enable X86 board specific fixups for reboot"
1284	depends on X86_32
1285	help
1286	  This enables chipset and/or board specific fixups to be done
1287	  in order to get reboot to work correctly. This is only needed on
1288	  some combinations of hardware and BIOS. The symptom, for which
1289	  this config is intended, is when reboot ends with a stalled/hung
1290	  system.
1291
1292	  Currently, the only fixup is for the Geode machines using
1293	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1294
1295	  Say Y if you want to enable the fixup. Currently, it's safe to
1296	  enable this option even if you don't need it.
1297	  Say N otherwise.
1298
1299config MICROCODE
1300	bool "CPU microcode loading support"
1301	default y
1302	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1303	help
1304	  If you say Y here, you will be able to update the microcode on
1305	  Intel and AMD processors. The Intel support is for the IA32 family,
1306	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1307	  AMD support is for families 0x10 and later. You will obviously need
1308	  the actual microcode binary data itself which is not shipped with
1309	  the Linux kernel.
1310
1311	  The preferred method to load microcode from a detached initrd is described
1312	  in Documentation/x86/microcode.rst. For that you need to enable
1313	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1314	  initrd for microcode blobs.
1315
1316	  In addition, you can build the microcode into the kernel. For that you
1317	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1318	  config option.
1319
1320config MICROCODE_INTEL
1321	bool "Intel microcode loading support"
1322	depends on CPU_SUP_INTEL && MICROCODE
1323	default MICROCODE
1324	help
1325	  This options enables microcode patch loading support for Intel
1326	  processors.
1327
1328	  For the current Intel microcode data package go to
1329	  <https://downloadcenter.intel.com> and search for
1330	  'Linux Processor Microcode Data File'.
1331
1332config MICROCODE_AMD
1333	bool "AMD microcode loading support"
1334	depends on CPU_SUP_AMD && MICROCODE
1335	help
1336	  If you select this option, microcode patch loading support for AMD
1337	  processors will be enabled.
1338
1339config MICROCODE_OLD_INTERFACE
1340	bool "Ancient loading interface (DEPRECATED)"
1341	default n
1342	depends on MICROCODE
1343	help
1344	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1345	  which was used by userspace tools like iucode_tool and microcode.ctl.
1346	  It is inadequate because it runs too late to be able to properly
1347	  load microcode on a machine and it needs special tools. Instead, you
1348	  should've switched to the early loading method with the initrd or
1349	  builtin microcode by now: Documentation/x86/microcode.rst
1350
1351config X86_MSR
1352	tristate "/dev/cpu/*/msr - Model-specific register support"
1353	help
1354	  This device gives privileged processes access to the x86
1355	  Model-Specific Registers (MSRs).  It is a character device with
1356	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1357	  MSR accesses are directed to a specific CPU on multi-processor
1358	  systems.
1359
1360config X86_CPUID
1361	tristate "/dev/cpu/*/cpuid - CPU information support"
1362	help
1363	  This device gives processes access to the x86 CPUID instruction to
1364	  be executed on a specific processor.  It is a character device
1365	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1366	  /dev/cpu/31/cpuid.
1367
1368choice
1369	prompt "High Memory Support"
1370	default HIGHMEM4G
1371	depends on X86_32
1372
1373config NOHIGHMEM
1374	bool "off"
1375	help
1376	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1377	  However, the address space of 32-bit x86 processors is only 4
1378	  Gigabytes large. That means that, if you have a large amount of
1379	  physical memory, not all of it can be "permanently mapped" by the
1380	  kernel. The physical memory that's not permanently mapped is called
1381	  "high memory".
1382
1383	  If you are compiling a kernel which will never run on a machine with
1384	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1385	  choice and suitable for most users). This will result in a "3GB/1GB"
1386	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1387	  space and the remaining part of the 4GB virtual memory space is used
1388	  by the kernel to permanently map as much physical memory as
1389	  possible.
1390
1391	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1392	  answer "4GB" here.
1393
1394	  If more than 4 Gigabytes is used then answer "64GB" here. This
1395	  selection turns Intel PAE (Physical Address Extension) mode on.
1396	  PAE implements 3-level paging on IA32 processors. PAE is fully
1397	  supported by Linux, PAE mode is implemented on all recent Intel
1398	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1399	  then the kernel will not boot on CPUs that don't support PAE!
1400
1401	  The actual amount of total physical memory will either be
1402	  auto detected or can be forced by using a kernel command line option
1403	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1404	  your boot loader (lilo or loadlin) about how to pass options to the
1405	  kernel at boot time.)
1406
1407	  If unsure, say "off".
1408
1409config HIGHMEM4G
1410	bool "4GB"
1411	help
1412	  Select this if you have a 32-bit processor and between 1 and 4
1413	  gigabytes of physical RAM.
1414
1415config HIGHMEM64G
1416	bool "64GB"
1417	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1418	select X86_PAE
1419	help
1420	  Select this if you have a 32-bit processor and more than 4
1421	  gigabytes of physical RAM.
1422
1423endchoice
1424
1425choice
1426	prompt "Memory split" if EXPERT
1427	default VMSPLIT_3G
1428	depends on X86_32
1429	help
1430	  Select the desired split between kernel and user memory.
1431
1432	  If the address range available to the kernel is less than the
1433	  physical memory installed, the remaining memory will be available
1434	  as "high memory". Accessing high memory is a little more costly
1435	  than low memory, as it needs to be mapped into the kernel first.
1436	  Note that increasing the kernel address space limits the range
1437	  available to user programs, making the address space there
1438	  tighter.  Selecting anything other than the default 3G/1G split
1439	  will also likely make your kernel incompatible with binary-only
1440	  kernel modules.
1441
1442	  If you are not absolutely sure what you are doing, leave this
1443	  option alone!
1444
1445	config VMSPLIT_3G
1446		bool "3G/1G user/kernel split"
1447	config VMSPLIT_3G_OPT
1448		depends on !X86_PAE
1449		bool "3G/1G user/kernel split (for full 1G low memory)"
1450	config VMSPLIT_2G
1451		bool "2G/2G user/kernel split"
1452	config VMSPLIT_2G_OPT
1453		depends on !X86_PAE
1454		bool "2G/2G user/kernel split (for full 2G low memory)"
1455	config VMSPLIT_1G
1456		bool "1G/3G user/kernel split"
1457endchoice
1458
1459config PAGE_OFFSET
1460	hex
1461	default 0xB0000000 if VMSPLIT_3G_OPT
1462	default 0x80000000 if VMSPLIT_2G
1463	default 0x78000000 if VMSPLIT_2G_OPT
1464	default 0x40000000 if VMSPLIT_1G
1465	default 0xC0000000
1466	depends on X86_32
1467
1468config HIGHMEM
1469	def_bool y
1470	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1471
1472config X86_PAE
1473	bool "PAE (Physical Address Extension) Support"
1474	depends on X86_32 && !HIGHMEM4G
1475	select PHYS_ADDR_T_64BIT
1476	select SWIOTLB
1477	help
1478	  PAE is required for NX support, and furthermore enables
1479	  larger swapspace support for non-overcommit purposes. It
1480	  has the cost of more pagetable lookup overhead, and also
1481	  consumes more pagetable space per process.
1482
1483config X86_5LEVEL
1484	bool "Enable 5-level page tables support"
1485	default y
1486	select DYNAMIC_MEMORY_LAYOUT
1487	select SPARSEMEM_VMEMMAP
1488	depends on X86_64
1489	help
1490	  5-level paging enables access to larger address space:
1491	  upto 128 PiB of virtual address space and 4 PiB of
1492	  physical address space.
1493
1494	  It will be supported by future Intel CPUs.
1495
1496	  A kernel with the option enabled can be booted on machines that
1497	  support 4- or 5-level paging.
1498
1499	  See Documentation/x86/x86_64/5level-paging.rst for more
1500	  information.
1501
1502	  Say N if unsure.
1503
1504config X86_DIRECT_GBPAGES
1505	def_bool y
1506	depends on X86_64
1507	help
1508	  Certain kernel features effectively disable kernel
1509	  linear 1 GB mappings (even if the CPU otherwise
1510	  supports them), so don't confuse the user by printing
1511	  that we have them enabled.
1512
1513config X86_CPA_STATISTICS
1514	bool "Enable statistic for Change Page Attribute"
1515	depends on DEBUG_FS
1516	help
1517	  Expose statistics about the Change Page Attribute mechanism, which
1518	  helps to determine the effectiveness of preserving large and huge
1519	  page mappings when mapping protections are changed.
1520
1521config AMD_MEM_ENCRYPT
1522	bool "AMD Secure Memory Encryption (SME) support"
1523	depends on X86_64 && CPU_SUP_AMD
1524	select DMA_COHERENT_POOL
1525	select DYNAMIC_PHYSICAL_MASK
1526	select ARCH_USE_MEMREMAP_PROT
1527	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1528	select INSTRUCTION_DECODER
1529	select ARCH_HAS_CC_PLATFORM
1530	help
1531	  Say yes to enable support for the encryption of system memory.
1532	  This requires an AMD processor that supports Secure Memory
1533	  Encryption (SME).
1534
1535config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1536	bool "Activate AMD Secure Memory Encryption (SME) by default"
1537	depends on AMD_MEM_ENCRYPT
1538	help
1539	  Say yes to have system memory encrypted by default if running on
1540	  an AMD processor that supports Secure Memory Encryption (SME).
1541
1542	  If set to Y, then the encryption of system memory can be
1543	  deactivated with the mem_encrypt=off command line option.
1544
1545	  If set to N, then the encryption of system memory can be
1546	  activated with the mem_encrypt=on command line option.
1547
1548# Common NUMA Features
1549config NUMA
1550	bool "NUMA Memory Allocation and Scheduler Support"
1551	depends on SMP
1552	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1553	default y if X86_BIGSMP
1554	help
1555	  Enable NUMA (Non-Uniform Memory Access) support.
1556
1557	  The kernel will try to allocate memory used by a CPU on the
1558	  local memory controller of the CPU and add some more
1559	  NUMA awareness to the kernel.
1560
1561	  For 64-bit this is recommended if the system is Intel Core i7
1562	  (or later), AMD Opteron, or EM64T NUMA.
1563
1564	  For 32-bit this is only needed if you boot a 32-bit
1565	  kernel on a 64-bit NUMA platform.
1566
1567	  Otherwise, you should say N.
1568
1569config AMD_NUMA
1570	def_bool y
1571	prompt "Old style AMD Opteron NUMA detection"
1572	depends on X86_64 && NUMA && PCI
1573	help
1574	  Enable AMD NUMA node topology detection.  You should say Y here if
1575	  you have a multi processor AMD system. This uses an old method to
1576	  read the NUMA configuration directly from the builtin Northbridge
1577	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1578	  which also takes priority if both are compiled in.
1579
1580config X86_64_ACPI_NUMA
1581	def_bool y
1582	prompt "ACPI NUMA detection"
1583	depends on X86_64 && NUMA && ACPI && PCI
1584	select ACPI_NUMA
1585	help
1586	  Enable ACPI SRAT based node topology detection.
1587
1588config NUMA_EMU
1589	bool "NUMA emulation"
1590	depends on NUMA
1591	help
1592	  Enable NUMA emulation. A flat machine will be split
1593	  into virtual nodes when booted with "numa=fake=N", where N is the
1594	  number of nodes. This is only useful for debugging.
1595
1596config NODES_SHIFT
1597	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1598	range 1 10
1599	default "10" if MAXSMP
1600	default "6" if X86_64
1601	default "3"
1602	depends on NEED_MULTIPLE_NODES
1603	help
1604	  Specify the maximum number of NUMA Nodes available on the target
1605	  system.  Increases memory reserved to accommodate various tables.
1606
1607config ARCH_FLATMEM_ENABLE
1608	def_bool y
1609	depends on X86_32 && !NUMA
1610
1611config ARCH_SPARSEMEM_ENABLE
1612	def_bool y
1613	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1614	select SPARSEMEM_STATIC if X86_32
1615	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1616
1617config ARCH_SPARSEMEM_DEFAULT
1618	def_bool X86_64 || (NUMA && X86_32)
1619
1620config ARCH_SELECT_MEMORY_MODEL
1621	def_bool y
1622	depends on ARCH_SPARSEMEM_ENABLE
1623
1624config ARCH_MEMORY_PROBE
1625	bool "Enable sysfs memory/probe interface"
1626	depends on X86_64 && MEMORY_HOTPLUG
1627	help
1628	  This option enables a sysfs memory/probe interface for testing.
1629	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1630	  If you are unsure how to answer this question, answer N.
1631
1632config ARCH_PROC_KCORE_TEXT
1633	def_bool y
1634	depends on X86_64 && PROC_KCORE
1635
1636config ILLEGAL_POINTER_VALUE
1637	hex
1638	default 0 if X86_32
1639	default 0xdead000000000000 if X86_64
1640
1641config X86_PMEM_LEGACY_DEVICE
1642	bool
1643
1644config X86_PMEM_LEGACY
1645	tristate "Support non-standard NVDIMMs and ADR protected memory"
1646	depends on PHYS_ADDR_T_64BIT
1647	depends on BLK_DEV
1648	select X86_PMEM_LEGACY_DEVICE
1649	select NUMA_KEEP_MEMINFO if NUMA
1650	select LIBNVDIMM
1651	help
1652	  Treat memory marked using the non-standard e820 type of 12 as used
1653	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1654	  The kernel will offer these regions to the 'pmem' driver so
1655	  they can be used for persistent storage.
1656
1657	  Say Y if unsure.
1658
1659config HIGHPTE
1660	bool "Allocate 3rd-level pagetables from highmem"
1661	depends on HIGHMEM
1662	help
1663	  The VM uses one page table entry for each page of physical memory.
1664	  For systems with a lot of RAM, this can be wasteful of precious
1665	  low memory.  Setting this option will put user-space page table
1666	  entries in high memory.
1667
1668config X86_CHECK_BIOS_CORRUPTION
1669	bool "Check for low memory corruption"
1670	help
1671	  Periodically check for memory corruption in low memory, which
1672	  is suspected to be caused by BIOS.  Even when enabled in the
1673	  configuration, it is disabled at runtime.  Enable it by
1674	  setting "memory_corruption_check=1" on the kernel command
1675	  line.  By default it scans the low 64k of memory every 60
1676	  seconds; see the memory_corruption_check_size and
1677	  memory_corruption_check_period parameters in
1678	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1679
1680	  When enabled with the default parameters, this option has
1681	  almost no overhead, as it reserves a relatively small amount
1682	  of memory and scans it infrequently.  It both detects corruption
1683	  and prevents it from affecting the running system.
1684
1685	  It is, however, intended as a diagnostic tool; if repeatable
1686	  BIOS-originated corruption always affects the same memory,
1687	  you can use memmap= to prevent the kernel from using that
1688	  memory.
1689
1690config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1691	bool "Set the default setting of memory_corruption_check"
1692	depends on X86_CHECK_BIOS_CORRUPTION
1693	default y
1694	help
1695	  Set whether the default state of memory_corruption_check is
1696	  on or off.
1697
1698config X86_RESERVE_LOW
1699	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1700	default 64
1701	range 4 640
1702	help
1703	  Specify the amount of low memory to reserve for the BIOS.
1704
1705	  The first page contains BIOS data structures that the kernel
1706	  must not use, so that page must always be reserved.
1707
1708	  By default we reserve the first 64K of physical RAM, as a
1709	  number of BIOSes are known to corrupt that memory range
1710	  during events such as suspend/resume or monitor cable
1711	  insertion, so it must not be used by the kernel.
1712
1713	  You can set this to 4 if you are absolutely sure that you
1714	  trust the BIOS to get all its memory reservations and usages
1715	  right.  If you know your BIOS have problems beyond the
1716	  default 64K area, you can set this to 640 to avoid using the
1717	  entire low memory range.
1718
1719	  If you have doubts about the BIOS (e.g. suspend/resume does
1720	  not work or there's kernel crashes after certain hardware
1721	  hotplug events) then you might want to enable
1722	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1723	  typical corruption patterns.
1724
1725	  Leave this to the default value of 64 if you are unsure.
1726
1727config MATH_EMULATION
1728	bool
1729	depends on MODIFY_LDT_SYSCALL
1730	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1731	help
1732	  Linux can emulate a math coprocessor (used for floating point
1733	  operations) if you don't have one. 486DX and Pentium processors have
1734	  a math coprocessor built in, 486SX and 386 do not, unless you added
1735	  a 487DX or 387, respectively. (The messages during boot time can
1736	  give you some hints here ["man dmesg"].) Everyone needs either a
1737	  coprocessor or this emulation.
1738
1739	  If you don't have a math coprocessor, you need to say Y here; if you
1740	  say Y here even though you have a coprocessor, the coprocessor will
1741	  be used nevertheless. (This behavior can be changed with the kernel
1742	  command line option "no387", which comes handy if your coprocessor
1743	  is broken. Try "man bootparam" or see the documentation of your boot
1744	  loader (lilo or loadlin) about how to pass options to the kernel at
1745	  boot time.) This means that it is a good idea to say Y here if you
1746	  intend to use this kernel on different machines.
1747
1748	  More information about the internals of the Linux math coprocessor
1749	  emulation can be found in <file:arch/x86/math-emu/README>.
1750
1751	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1752	  kernel, it won't hurt.
1753
1754config MTRR
1755	def_bool y
1756	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1757	help
1758	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1759	  the Memory Type Range Registers (MTRRs) may be used to control
1760	  processor access to memory ranges. This is most useful if you have
1761	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1762	  allows bus write transfers to be combined into a larger transfer
1763	  before bursting over the PCI/AGP bus. This can increase performance
1764	  of image write operations 2.5 times or more. Saying Y here creates a
1765	  /proc/mtrr file which may be used to manipulate your processor's
1766	  MTRRs. Typically the X server should use this.
1767
1768	  This code has a reasonably generic interface so that similar
1769	  control registers on other processors can be easily supported
1770	  as well:
1771
1772	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1773	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1774	  these, the ARRs are used to emulate the MTRRs.
1775	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1776	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1777	  write-combining. All of these processors are supported by this code
1778	  and it makes sense to say Y here if you have one of them.
1779
1780	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1781	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1782	  can lead to all sorts of problems, so it's good to say Y here.
1783
1784	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1785	  just add about 9 KB to your kernel.
1786
1787	  See <file:Documentation/x86/mtrr.rst> for more information.
1788
1789config MTRR_SANITIZER
1790	def_bool y
1791	prompt "MTRR cleanup support"
1792	depends on MTRR
1793	help
1794	  Convert MTRR layout from continuous to discrete, so X drivers can
1795	  add writeback entries.
1796
1797	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1798	  The largest mtrr entry size for a continuous block can be set with
1799	  mtrr_chunk_size.
1800
1801	  If unsure, say Y.
1802
1803config MTRR_SANITIZER_ENABLE_DEFAULT
1804	int "MTRR cleanup enable value (0-1)"
1805	range 0 1
1806	default "0"
1807	depends on MTRR_SANITIZER
1808	help
1809	  Enable mtrr cleanup default value
1810
1811config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1812	int "MTRR cleanup spare reg num (0-7)"
1813	range 0 7
1814	default "1"
1815	depends on MTRR_SANITIZER
1816	help
1817	  mtrr cleanup spare entries default, it can be changed via
1818	  mtrr_spare_reg_nr=N on the kernel command line.
1819
1820config X86_PAT
1821	def_bool y
1822	prompt "x86 PAT support" if EXPERT
1823	depends on MTRR
1824	help
1825	  Use PAT attributes to setup page level cache control.
1826
1827	  PATs are the modern equivalents of MTRRs and are much more
1828	  flexible than MTRRs.
1829
1830	  Say N here if you see bootup problems (boot crash, boot hang,
1831	  spontaneous reboots) or a non-working video driver.
1832
1833	  If unsure, say Y.
1834
1835config ARCH_USES_PG_UNCACHED
1836	def_bool y
1837	depends on X86_PAT
1838
1839config ARCH_RANDOM
1840	def_bool y
1841	prompt "x86 architectural random number generator" if EXPERT
1842	help
1843	  Enable the x86 architectural RDRAND instruction
1844	  (Intel Bull Mountain technology) to generate random numbers.
1845	  If supported, this is a high bandwidth, cryptographically
1846	  secure hardware random number generator.
1847
1848config X86_SMAP
1849	def_bool y
1850	prompt "Supervisor Mode Access Prevention" if EXPERT
1851	help
1852	  Supervisor Mode Access Prevention (SMAP) is a security
1853	  feature in newer Intel processors.  There is a small
1854	  performance cost if this enabled and turned on; there is
1855	  also a small increase in the kernel size if this is enabled.
1856
1857	  If unsure, say Y.
1858
1859config X86_UMIP
1860	def_bool y
1861	prompt "User Mode Instruction Prevention" if EXPERT
1862	help
1863	  User Mode Instruction Prevention (UMIP) is a security feature in
1864	  some x86 processors. If enabled, a general protection fault is
1865	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1866	  executed in user mode. These instructions unnecessarily expose
1867	  information about the hardware state.
1868
1869	  The vast majority of applications do not use these instructions.
1870	  For the very few that do, software emulation is provided in
1871	  specific cases in protected and virtual-8086 modes. Emulated
1872	  results are dummy.
1873
1874config X86_INTEL_MEMORY_PROTECTION_KEYS
1875	prompt "Memory Protection Keys"
1876	def_bool y
1877	# Note: only available in 64-bit mode
1878	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1879	select ARCH_USES_HIGH_VMA_FLAGS
1880	select ARCH_HAS_PKEYS
1881	help
1882	  Memory Protection Keys provides a mechanism for enforcing
1883	  page-based protections, but without requiring modification of the
1884	  page tables when an application changes protection domains.
1885
1886	  For details, see Documentation/core-api/protection-keys.rst
1887
1888	  If unsure, say y.
1889
1890choice
1891	prompt "TSX enable mode"
1892	depends on CPU_SUP_INTEL
1893	default X86_INTEL_TSX_MODE_OFF
1894	help
1895	  Intel's TSX (Transactional Synchronization Extensions) feature
1896	  allows to optimize locking protocols through lock elision which
1897	  can lead to a noticeable performance boost.
1898
1899	  On the other hand it has been shown that TSX can be exploited
1900	  to form side channel attacks (e.g. TAA) and chances are there
1901	  will be more of those attacks discovered in the future.
1902
1903	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1904	  might override this decision by tsx=on the command line parameter.
1905	  Even with TSX enabled, the kernel will attempt to enable the best
1906	  possible TAA mitigation setting depending on the microcode available
1907	  for the particular machine.
1908
1909	  This option allows to set the default tsx mode between tsx=on, =off
1910	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1911	  details.
1912
1913	  Say off if not sure, auto if TSX is in use but it should be used on safe
1914	  platforms or on if TSX is in use and the security aspect of tsx is not
1915	  relevant.
1916
1917config X86_INTEL_TSX_MODE_OFF
1918	bool "off"
1919	help
1920	  TSX is disabled if possible - equals to tsx=off command line parameter.
1921
1922config X86_INTEL_TSX_MODE_ON
1923	bool "on"
1924	help
1925	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1926	  line parameter.
1927
1928config X86_INTEL_TSX_MODE_AUTO
1929	bool "auto"
1930	help
1931	  TSX is enabled on TSX capable HW that is believed to be safe against
1932	  side channel attacks- equals the tsx=auto command line parameter.
1933endchoice
1934
1935config EFI
1936	bool "EFI runtime service support"
1937	depends on ACPI
1938	select UCS2_STRING
1939	select EFI_RUNTIME_WRAPPERS
1940	select ARCH_USE_MEMREMAP_PROT
1941	help
1942	  This enables the kernel to use EFI runtime services that are
1943	  available (such as the EFI variable services).
1944
1945	  This option is only useful on systems that have EFI firmware.
1946	  In addition, you should use the latest ELILO loader available
1947	  at <http://elilo.sourceforge.net> in order to take advantage
1948	  of EFI runtime services. However, even with this option, the
1949	  resultant kernel should continue to boot on existing non-EFI
1950	  platforms.
1951
1952config EFI_STUB
1953	bool "EFI stub support"
1954	depends on EFI && !X86_USE_3DNOW
1955	select RELOCATABLE
1956	help
1957	  This kernel feature allows a bzImage to be loaded directly
1958	  by EFI firmware without the use of a bootloader.
1959
1960	  See Documentation/admin-guide/efi-stub.rst for more information.
1961
1962config EFI_MIXED
1963	bool "EFI mixed-mode support"
1964	depends on EFI_STUB && X86_64
1965	help
1966	   Enabling this feature allows a 64-bit kernel to be booted
1967	   on a 32-bit firmware, provided that your CPU supports 64-bit
1968	   mode.
1969
1970	   Note that it is not possible to boot a mixed-mode enabled
1971	   kernel via the EFI boot stub - a bootloader that supports
1972	   the EFI handover protocol must be used.
1973
1974	   If unsure, say N.
1975
1976source "kernel/Kconfig.hz"
1977
1978config KEXEC
1979	bool "kexec system call"
1980	select KEXEC_CORE
1981	help
1982	  kexec is a system call that implements the ability to shutdown your
1983	  current kernel, and to start another kernel.  It is like a reboot
1984	  but it is independent of the system firmware.   And like a reboot
1985	  you can start any kernel with it, not just Linux.
1986
1987	  The name comes from the similarity to the exec system call.
1988
1989	  It is an ongoing process to be certain the hardware in a machine
1990	  is properly shutdown, so do not be surprised if this code does not
1991	  initially work for you.  As of this writing the exact hardware
1992	  interface is strongly in flux, so no good recommendation can be
1993	  made.
1994
1995config KEXEC_FILE
1996	bool "kexec file based system call"
1997	select KEXEC_CORE
1998	select BUILD_BIN2C
1999	depends on X86_64
2000	depends on CRYPTO=y
2001	depends on CRYPTO_SHA256=y
2002	help
2003	  This is new version of kexec system call. This system call is
2004	  file based and takes file descriptors as system call argument
2005	  for kernel and initramfs as opposed to list of segments as
2006	  accepted by previous system call.
2007
2008config ARCH_HAS_KEXEC_PURGATORY
2009	def_bool KEXEC_FILE
2010
2011config KEXEC_SIG
2012	bool "Verify kernel signature during kexec_file_load() syscall"
2013	depends on KEXEC_FILE
2014	help
2015
2016	  This option makes the kexec_file_load() syscall check for a valid
2017	  signature of the kernel image.  The image can still be loaded without
2018	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2019	  there's a signature that we can check, then it must be valid.
2020
2021	  In addition to this option, you need to enable signature
2022	  verification for the corresponding kernel image type being
2023	  loaded in order for this to work.
2024
2025config KEXEC_SIG_FORCE
2026	bool "Require a valid signature in kexec_file_load() syscall"
2027	depends on KEXEC_SIG
2028	help
2029	  This option makes kernel signature verification mandatory for
2030	  the kexec_file_load() syscall.
2031
2032config KEXEC_BZIMAGE_VERIFY_SIG
2033	bool "Enable bzImage signature verification support"
2034	depends on KEXEC_SIG
2035	depends on SIGNED_PE_FILE_VERIFICATION
2036	select SYSTEM_TRUSTED_KEYRING
2037	help
2038	  Enable bzImage signature verification support.
2039
2040config CRASH_DUMP
2041	bool "kernel crash dumps"
2042	depends on X86_64 || (X86_32 && HIGHMEM)
2043	help
2044	  Generate crash dump after being started by kexec.
2045	  This should be normally only set in special crash dump kernels
2046	  which are loaded in the main kernel with kexec-tools into
2047	  a specially reserved region and then later executed after
2048	  a crash by kdump/kexec. The crash dump kernel must be compiled
2049	  to a memory address not used by the main kernel or BIOS using
2050	  PHYSICAL_START, or it must be built as a relocatable image
2051	  (CONFIG_RELOCATABLE=y).
2052	  For more details see Documentation/admin-guide/kdump/kdump.rst
2053
2054config KEXEC_JUMP
2055	bool "kexec jump"
2056	depends on KEXEC && HIBERNATION
2057	help
2058	  Jump between original kernel and kexeced kernel and invoke
2059	  code in physical address mode via KEXEC
2060
2061config PHYSICAL_START
2062	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2063	default "0x1000000"
2064	help
2065	  This gives the physical address where the kernel is loaded.
2066
2067	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2068	  bzImage will decompress itself to above physical address and
2069	  run from there. Otherwise, bzImage will run from the address where
2070	  it has been loaded by the boot loader and will ignore above physical
2071	  address.
2072
2073	  In normal kdump cases one does not have to set/change this option
2074	  as now bzImage can be compiled as a completely relocatable image
2075	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2076	  address. This option is mainly useful for the folks who don't want
2077	  to use a bzImage for capturing the crash dump and want to use a
2078	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2079	  to be specifically compiled to run from a specific memory area
2080	  (normally a reserved region) and this option comes handy.
2081
2082	  So if you are using bzImage for capturing the crash dump,
2083	  leave the value here unchanged to 0x1000000 and set
2084	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2085	  for capturing the crash dump change this value to start of
2086	  the reserved region.  In other words, it can be set based on
2087	  the "X" value as specified in the "crashkernel=YM@XM"
2088	  command line boot parameter passed to the panic-ed
2089	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2090	  for more details about crash dumps.
2091
2092	  Usage of bzImage for capturing the crash dump is recommended as
2093	  one does not have to build two kernels. Same kernel can be used
2094	  as production kernel and capture kernel. Above option should have
2095	  gone away after relocatable bzImage support is introduced. But it
2096	  is present because there are users out there who continue to use
2097	  vmlinux for dump capture. This option should go away down the
2098	  line.
2099
2100	  Don't change this unless you know what you are doing.
2101
2102config RELOCATABLE
2103	bool "Build a relocatable kernel"
2104	default y
2105	help
2106	  This builds a kernel image that retains relocation information
2107	  so it can be loaded someplace besides the default 1MB.
2108	  The relocations tend to make the kernel binary about 10% larger,
2109	  but are discarded at runtime.
2110
2111	  One use is for the kexec on panic case where the recovery kernel
2112	  must live at a different physical address than the primary
2113	  kernel.
2114
2115	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2116	  it has been loaded at and the compile time physical address
2117	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2118
2119config RANDOMIZE_BASE
2120	bool "Randomize the address of the kernel image (KASLR)"
2121	depends on RELOCATABLE
2122	default y
2123	help
2124	  In support of Kernel Address Space Layout Randomization (KASLR),
2125	  this randomizes the physical address at which the kernel image
2126	  is decompressed and the virtual address where the kernel
2127	  image is mapped, as a security feature that deters exploit
2128	  attempts relying on knowledge of the location of kernel
2129	  code internals.
2130
2131	  On 64-bit, the kernel physical and virtual addresses are
2132	  randomized separately. The physical address will be anywhere
2133	  between 16MB and the top of physical memory (up to 64TB). The
2134	  virtual address will be randomized from 16MB up to 1GB (9 bits
2135	  of entropy). Note that this also reduces the memory space
2136	  available to kernel modules from 1.5GB to 1GB.
2137
2138	  On 32-bit, the kernel physical and virtual addresses are
2139	  randomized together. They will be randomized from 16MB up to
2140	  512MB (8 bits of entropy).
2141
2142	  Entropy is generated using the RDRAND instruction if it is
2143	  supported. If RDTSC is supported, its value is mixed into
2144	  the entropy pool as well. If neither RDRAND nor RDTSC are
2145	  supported, then entropy is read from the i8254 timer. The
2146	  usable entropy is limited by the kernel being built using
2147	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2148	  minimum of 2MB. As a result, only 10 bits of entropy are
2149	  theoretically possible, but the implementations are further
2150	  limited due to memory layouts.
2151
2152	  If unsure, say Y.
2153
2154# Relocation on x86 needs some additional build support
2155config X86_NEED_RELOCS
2156	def_bool y
2157	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2158
2159config PHYSICAL_ALIGN
2160	hex "Alignment value to which kernel should be aligned"
2161	default "0x200000"
2162	range 0x2000 0x1000000 if X86_32
2163	range 0x200000 0x1000000 if X86_64
2164	help
2165	  This value puts the alignment restrictions on physical address
2166	  where kernel is loaded and run from. Kernel is compiled for an
2167	  address which meets above alignment restriction.
2168
2169	  If bootloader loads the kernel at a non-aligned address and
2170	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2171	  address aligned to above value and run from there.
2172
2173	  If bootloader loads the kernel at a non-aligned address and
2174	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2175	  load address and decompress itself to the address it has been
2176	  compiled for and run from there. The address for which kernel is
2177	  compiled already meets above alignment restrictions. Hence the
2178	  end result is that kernel runs from a physical address meeting
2179	  above alignment restrictions.
2180
2181	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2182	  this value must be a multiple of 0x200000.
2183
2184	  Don't change this unless you know what you are doing.
2185
2186config DYNAMIC_MEMORY_LAYOUT
2187	bool
2188	help
2189	  This option makes base addresses of vmalloc and vmemmap as well as
2190	  __PAGE_OFFSET movable during boot.
2191
2192config RANDOMIZE_MEMORY
2193	bool "Randomize the kernel memory sections"
2194	depends on X86_64
2195	depends on RANDOMIZE_BASE
2196	select DYNAMIC_MEMORY_LAYOUT
2197	default RANDOMIZE_BASE
2198	help
2199	   Randomizes the base virtual address of kernel memory sections
2200	   (physical memory mapping, vmalloc & vmemmap). This security feature
2201	   makes exploits relying on predictable memory locations less reliable.
2202
2203	   The order of allocations remains unchanged. Entropy is generated in
2204	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2205	   configuration have in average 30,000 different possible virtual
2206	   addresses for each memory section.
2207
2208	   If unsure, say Y.
2209
2210config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2211	hex "Physical memory mapping padding" if EXPERT
2212	depends on RANDOMIZE_MEMORY
2213	default "0xa" if MEMORY_HOTPLUG
2214	default "0x0"
2215	range 0x1 0x40 if MEMORY_HOTPLUG
2216	range 0x0 0x40
2217	help
2218	   Define the padding in terabytes added to the existing physical
2219	   memory size during kernel memory randomization. It is useful
2220	   for memory hotplug support but reduces the entropy available for
2221	   address randomization.
2222
2223	   If unsure, leave at the default value.
2224
2225config HOTPLUG_CPU
2226	def_bool y
2227	depends on SMP
2228
2229config BOOTPARAM_HOTPLUG_CPU0
2230	bool "Set default setting of cpu0_hotpluggable"
2231	depends on HOTPLUG_CPU
2232	help
2233	  Set whether default state of cpu0_hotpluggable is on or off.
2234
2235	  Say Y here to enable CPU0 hotplug by default. If this switch
2236	  is turned on, there is no need to give cpu0_hotplug kernel
2237	  parameter and the CPU0 hotplug feature is enabled by default.
2238
2239	  Please note: there are two known CPU0 dependencies if you want
2240	  to enable the CPU0 hotplug feature either by this switch or by
2241	  cpu0_hotplug kernel parameter.
2242
2243	  First, resume from hibernate or suspend always starts from CPU0.
2244	  So hibernate and suspend are prevented if CPU0 is offline.
2245
2246	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2247	  offline if any interrupt can not migrate out of CPU0. There may
2248	  be other CPU0 dependencies.
2249
2250	  Please make sure the dependencies are under your control before
2251	  you enable this feature.
2252
2253	  Say N if you don't want to enable CPU0 hotplug feature by default.
2254	  You still can enable the CPU0 hotplug feature at boot by kernel
2255	  parameter cpu0_hotplug.
2256
2257config DEBUG_HOTPLUG_CPU0
2258	def_bool n
2259	prompt "Debug CPU0 hotplug"
2260	depends on HOTPLUG_CPU
2261	help
2262	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2263	  soon as possible and boots up userspace with CPU0 offlined. User
2264	  can online CPU0 back after boot time.
2265
2266	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2267	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2268	  compilation or giving cpu0_hotplug kernel parameter at boot.
2269
2270	  If unsure, say N.
2271
2272config COMPAT_VDSO
2273	def_bool n
2274	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2275	depends on COMPAT_32
2276	help
2277	  Certain buggy versions of glibc will crash if they are
2278	  presented with a 32-bit vDSO that is not mapped at the address
2279	  indicated in its segment table.
2280
2281	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2282	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2283	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2284	  the only released version with the bug, but OpenSUSE 9
2285	  contains a buggy "glibc 2.3.2".
2286
2287	  The symptom of the bug is that everything crashes on startup, saying:
2288	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2289
2290	  Saying Y here changes the default value of the vdso32 boot
2291	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2292	  This works around the glibc bug but hurts performance.
2293
2294	  If unsure, say N: if you are compiling your own kernel, you
2295	  are unlikely to be using a buggy version of glibc.
2296
2297choice
2298	prompt "vsyscall table for legacy applications"
2299	depends on X86_64
2300	default LEGACY_VSYSCALL_XONLY
2301	help
2302	  Legacy user code that does not know how to find the vDSO expects
2303	  to be able to issue three syscalls by calling fixed addresses in
2304	  kernel space. Since this location is not randomized with ASLR,
2305	  it can be used to assist security vulnerability exploitation.
2306
2307	  This setting can be changed at boot time via the kernel command
2308	  line parameter vsyscall=[emulate|xonly|none].
2309
2310	  On a system with recent enough glibc (2.14 or newer) and no
2311	  static binaries, you can say None without a performance penalty
2312	  to improve security.
2313
2314	  If unsure, select "Emulate execution only".
2315
2316	config LEGACY_VSYSCALL_EMULATE
2317		bool "Full emulation"
2318		help
2319		  The kernel traps and emulates calls into the fixed vsyscall
2320		  address mapping. This makes the mapping non-executable, but
2321		  it still contains readable known contents, which could be
2322		  used in certain rare security vulnerability exploits. This
2323		  configuration is recommended when using legacy userspace
2324		  that still uses vsyscalls along with legacy binary
2325		  instrumentation tools that require code to be readable.
2326
2327		  An example of this type of legacy userspace is running
2328		  Pin on an old binary that still uses vsyscalls.
2329
2330	config LEGACY_VSYSCALL_XONLY
2331		bool "Emulate execution only"
2332		help
2333		  The kernel traps and emulates calls into the fixed vsyscall
2334		  address mapping and does not allow reads.  This
2335		  configuration is recommended when userspace might use the
2336		  legacy vsyscall area but support for legacy binary
2337		  instrumentation of legacy code is not needed.  It mitigates
2338		  certain uses of the vsyscall area as an ASLR-bypassing
2339		  buffer.
2340
2341	config LEGACY_VSYSCALL_NONE
2342		bool "None"
2343		help
2344		  There will be no vsyscall mapping at all. This will
2345		  eliminate any risk of ASLR bypass due to the vsyscall
2346		  fixed address mapping. Attempts to use the vsyscalls
2347		  will be reported to dmesg, so that either old or
2348		  malicious userspace programs can be identified.
2349
2350endchoice
2351
2352config CMDLINE_BOOL
2353	bool "Built-in kernel command line"
2354	help
2355	  Allow for specifying boot arguments to the kernel at
2356	  build time.  On some systems (e.g. embedded ones), it is
2357	  necessary or convenient to provide some or all of the
2358	  kernel boot arguments with the kernel itself (that is,
2359	  to not rely on the boot loader to provide them.)
2360
2361	  To compile command line arguments into the kernel,
2362	  set this option to 'Y', then fill in the
2363	  boot arguments in CONFIG_CMDLINE.
2364
2365	  Systems with fully functional boot loaders (i.e. non-embedded)
2366	  should leave this option set to 'N'.
2367
2368config CMDLINE
2369	string "Built-in kernel command string"
2370	depends on CMDLINE_BOOL
2371	default ""
2372	help
2373	  Enter arguments here that should be compiled into the kernel
2374	  image and used at boot time.  If the boot loader provides a
2375	  command line at boot time, it is appended to this string to
2376	  form the full kernel command line, when the system boots.
2377
2378	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2379	  change this behavior.
2380
2381	  In most cases, the command line (whether built-in or provided
2382	  by the boot loader) should specify the device for the root
2383	  file system.
2384
2385config CMDLINE_OVERRIDE
2386	bool "Built-in command line overrides boot loader arguments"
2387	depends on CMDLINE_BOOL && CMDLINE != ""
2388	help
2389	  Set this option to 'Y' to have the kernel ignore the boot loader
2390	  command line, and use ONLY the built-in command line.
2391
2392	  This is used to work around broken boot loaders.  This should
2393	  be set to 'N' under normal conditions.
2394
2395config MODIFY_LDT_SYSCALL
2396	bool "Enable the LDT (local descriptor table)" if EXPERT
2397	default y
2398	help
2399	  Linux can allow user programs to install a per-process x86
2400	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2401	  call.  This is required to run 16-bit or segmented code such as
2402	  DOSEMU or some Wine programs.  It is also used by some very old
2403	  threading libraries.
2404
2405	  Enabling this feature adds a small amount of overhead to
2406	  context switches and increases the low-level kernel attack
2407	  surface.  Disabling it removes the modify_ldt(2) system call.
2408
2409	  Saying 'N' here may make sense for embedded or server kernels.
2410
2411source "kernel/livepatch/Kconfig"
2412
2413endmenu
2414
2415config CC_HAS_SLS
2416	def_bool $(cc-option,-mharden-sls=all)
2417
2418config CC_HAS_RETURN_THUNK
2419	def_bool $(cc-option,-mfunction-return=thunk-extern)
2420
2421menuconfig SPECULATION_MITIGATIONS
2422	bool "Mitigations for speculative execution vulnerabilities"
2423	default y
2424	help
2425	  Say Y here to enable options which enable mitigations for
2426	  speculative execution hardware vulnerabilities.
2427
2428	  If you say N, all mitigations will be disabled. You really
2429	  should know what you are doing to say so.
2430
2431if SPECULATION_MITIGATIONS
2432
2433config PAGE_TABLE_ISOLATION
2434	bool "Remove the kernel mapping in user mode"
2435	default y
2436	depends on (X86_64 || X86_PAE)
2437	help
2438	  This feature reduces the number of hardware side channels by
2439	  ensuring that the majority of kernel addresses are not mapped
2440	  into userspace.
2441
2442	  See Documentation/x86/pti.rst for more details.
2443
2444config RETPOLINE
2445	bool "Avoid speculative indirect branches in kernel"
2446	default y
2447	help
2448	  Compile kernel with the retpoline compiler options to guard against
2449	  kernel-to-user data leaks by avoiding speculative indirect
2450	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2451	  support for full protection. The kernel may run slower.
2452
2453config RETHUNK
2454	bool "Enable return-thunks"
2455	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2456	default y if X86_64
2457	help
2458	  Compile the kernel with the return-thunks compiler option to guard
2459	  against kernel-to-user data leaks by avoiding return speculation.
2460	  Requires a compiler with -mfunction-return=thunk-extern
2461	  support for full protection. The kernel may run slower.
2462
2463config CPU_UNRET_ENTRY
2464	bool "Enable UNRET on kernel entry"
2465	depends on CPU_SUP_AMD && RETHUNK && X86_64
2466	default y
2467	help
2468	  Compile the kernel with support for the retbleed=unret mitigation.
2469
2470config CPU_IBPB_ENTRY
2471	bool "Enable IBPB on kernel entry"
2472	depends on CPU_SUP_AMD && X86_64
2473	default y
2474	help
2475	  Compile the kernel with support for the retbleed=ibpb mitigation.
2476
2477config CPU_IBRS_ENTRY
2478	bool "Enable IBRS on kernel entry"
2479	depends on CPU_SUP_INTEL && X86_64
2480	default y
2481	help
2482	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2483	  This mitigates both spectre_v2 and retbleed at great cost to
2484	  performance.
2485
2486config SLS
2487	bool "Mitigate Straight-Line-Speculation"
2488	depends on CC_HAS_SLS && X86_64
2489	default n
2490	help
2491	  Compile the kernel with straight-line-speculation options to guard
2492	  against straight line speculation. The kernel image might be slightly
2493	  larger.
2494
2495endif
2496
2497config ARCH_HAS_ADD_PAGES
2498	def_bool y
2499	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2500
2501config ARCH_ENABLE_MEMORY_HOTPLUG
2502	def_bool y
2503	depends on X86_64 || (X86_32 && HIGHMEM)
2504
2505config ARCH_ENABLE_MEMORY_HOTREMOVE
2506	def_bool y
2507	depends on MEMORY_HOTPLUG
2508
2509config USE_PERCPU_NUMA_NODE_ID
2510	def_bool y
2511	depends on NUMA
2512
2513config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2514	def_bool y
2515	depends on X86_64 || X86_PAE
2516
2517config ARCH_ENABLE_HUGEPAGE_MIGRATION
2518	def_bool y
2519	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2520
2521config ARCH_ENABLE_THP_MIGRATION
2522	def_bool y
2523	depends on X86_64 && TRANSPARENT_HUGEPAGE
2524
2525menu "Power management and ACPI options"
2526
2527config ARCH_HIBERNATION_HEADER
2528	def_bool y
2529	depends on HIBERNATION
2530
2531source "kernel/power/Kconfig"
2532
2533source "drivers/acpi/Kconfig"
2534
2535source "drivers/sfi/Kconfig"
2536
2537config X86_APM_BOOT
2538	def_bool y
2539	depends on APM
2540
2541menuconfig APM
2542	tristate "APM (Advanced Power Management) BIOS support"
2543	depends on X86_32 && PM_SLEEP
2544	help
2545	  APM is a BIOS specification for saving power using several different
2546	  techniques. This is mostly useful for battery powered laptops with
2547	  APM compliant BIOSes. If you say Y here, the system time will be
2548	  reset after a RESUME operation, the /proc/apm device will provide
2549	  battery status information, and user-space programs will receive
2550	  notification of APM "events" (e.g. battery status change).
2551
2552	  If you select "Y" here, you can disable actual use of the APM
2553	  BIOS by passing the "apm=off" option to the kernel at boot time.
2554
2555	  Note that the APM support is almost completely disabled for
2556	  machines with more than one CPU.
2557
2558	  In order to use APM, you will need supporting software. For location
2559	  and more information, read <file:Documentation/power/apm-acpi.rst>
2560	  and the Battery Powered Linux mini-HOWTO, available from
2561	  <http://www.tldp.org/docs.html#howto>.
2562
2563	  This driver does not spin down disk drives (see the hdparm(8)
2564	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2565	  VESA-compliant "green" monitors.
2566
2567	  This driver does not support the TI 4000M TravelMate and the ACER
2568	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2569	  desktop machines also don't have compliant BIOSes, and this driver
2570	  may cause those machines to panic during the boot phase.
2571
2572	  Generally, if you don't have a battery in your machine, there isn't
2573	  much point in using this driver and you should say N. If you get
2574	  random kernel OOPSes or reboots that don't seem to be related to
2575	  anything, try disabling/enabling this option (or disabling/enabling
2576	  APM in your BIOS).
2577
2578	  Some other things you should try when experiencing seemingly random,
2579	  "weird" problems:
2580
2581	  1) make sure that you have enough swap space and that it is
2582	  enabled.
2583	  2) pass the "no-hlt" option to the kernel
2584	  3) switch on floating point emulation in the kernel and pass
2585	  the "no387" option to the kernel
2586	  4) pass the "floppy=nodma" option to the kernel
2587	  5) pass the "mem=4M" option to the kernel (thereby disabling
2588	  all but the first 4 MB of RAM)
2589	  6) make sure that the CPU is not over clocked.
2590	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2591	  8) disable the cache from your BIOS settings
2592	  9) install a fan for the video card or exchange video RAM
2593	  10) install a better fan for the CPU
2594	  11) exchange RAM chips
2595	  12) exchange the motherboard.
2596
2597	  To compile this driver as a module, choose M here: the
2598	  module will be called apm.
2599
2600if APM
2601
2602config APM_IGNORE_USER_SUSPEND
2603	bool "Ignore USER SUSPEND"
2604	help
2605	  This option will ignore USER SUSPEND requests. On machines with a
2606	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2607	  series notebooks, it is necessary to say Y because of a BIOS bug.
2608
2609config APM_DO_ENABLE
2610	bool "Enable PM at boot time"
2611	help
2612	  Enable APM features at boot time. From page 36 of the APM BIOS
2613	  specification: "When disabled, the APM BIOS does not automatically
2614	  power manage devices, enter the Standby State, enter the Suspend
2615	  State, or take power saving steps in response to CPU Idle calls."
2616	  This driver will make CPU Idle calls when Linux is idle (unless this
2617	  feature is turned off -- see "Do CPU IDLE calls", below). This
2618	  should always save battery power, but more complicated APM features
2619	  will be dependent on your BIOS implementation. You may need to turn
2620	  this option off if your computer hangs at boot time when using APM
2621	  support, or if it beeps continuously instead of suspending. Turn
2622	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2623	  T400CDT. This is off by default since most machines do fine without
2624	  this feature.
2625
2626config APM_CPU_IDLE
2627	depends on CPU_IDLE
2628	bool "Make CPU Idle calls when idle"
2629	help
2630	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2631	  On some machines, this can activate improved power savings, such as
2632	  a slowed CPU clock rate, when the machine is idle. These idle calls
2633	  are made after the idle loop has run for some length of time (e.g.,
2634	  333 mS). On some machines, this will cause a hang at boot time or
2635	  whenever the CPU becomes idle. (On machines with more than one CPU,
2636	  this option does nothing.)
2637
2638config APM_DISPLAY_BLANK
2639	bool "Enable console blanking using APM"
2640	help
2641	  Enable console blanking using the APM. Some laptops can use this to
2642	  turn off the LCD backlight when the screen blanker of the Linux
2643	  virtual console blanks the screen. Note that this is only used by
2644	  the virtual console screen blanker, and won't turn off the backlight
2645	  when using the X Window system. This also doesn't have anything to
2646	  do with your VESA-compliant power-saving monitor. Further, this
2647	  option doesn't work for all laptops -- it might not turn off your
2648	  backlight at all, or it might print a lot of errors to the console,
2649	  especially if you are using gpm.
2650
2651config APM_ALLOW_INTS
2652	bool "Allow interrupts during APM BIOS calls"
2653	help
2654	  Normally we disable external interrupts while we are making calls to
2655	  the APM BIOS as a measure to lessen the effects of a badly behaving
2656	  BIOS implementation.  The BIOS should reenable interrupts if it
2657	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2658	  many of the newer IBM Thinkpads.  If you experience hangs when you
2659	  suspend, try setting this to Y.  Otherwise, say N.
2660
2661endif # APM
2662
2663source "drivers/cpufreq/Kconfig"
2664
2665source "drivers/cpuidle/Kconfig"
2666
2667source "drivers/idle/Kconfig"
2668
2669endmenu
2670
2671
2672menu "Bus options (PCI etc.)"
2673
2674choice
2675	prompt "PCI access mode"
2676	depends on X86_32 && PCI
2677	default PCI_GOANY
2678	help
2679	  On PCI systems, the BIOS can be used to detect the PCI devices and
2680	  determine their configuration. However, some old PCI motherboards
2681	  have BIOS bugs and may crash if this is done. Also, some embedded
2682	  PCI-based systems don't have any BIOS at all. Linux can also try to
2683	  detect the PCI hardware directly without using the BIOS.
2684
2685	  With this option, you can specify how Linux should detect the
2686	  PCI devices. If you choose "BIOS", the BIOS will be used,
2687	  if you choose "Direct", the BIOS won't be used, and if you
2688	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2689	  If you choose "Any", the kernel will try MMCONFIG, then the
2690	  direct access method and falls back to the BIOS if that doesn't
2691	  work. If unsure, go with the default, which is "Any".
2692
2693config PCI_GOBIOS
2694	bool "BIOS"
2695
2696config PCI_GOMMCONFIG
2697	bool "MMConfig"
2698
2699config PCI_GODIRECT
2700	bool "Direct"
2701
2702config PCI_GOOLPC
2703	bool "OLPC XO-1"
2704	depends on OLPC
2705
2706config PCI_GOANY
2707	bool "Any"
2708
2709endchoice
2710
2711config PCI_BIOS
2712	def_bool y
2713	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2714
2715# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2716config PCI_DIRECT
2717	def_bool y
2718	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2719
2720config PCI_MMCONFIG
2721	bool "Support mmconfig PCI config space access" if X86_64
2722	default y
2723	depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2724	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2725
2726config PCI_OLPC
2727	def_bool y
2728	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2729
2730config PCI_XEN
2731	def_bool y
2732	depends on PCI && XEN
2733	select SWIOTLB_XEN
2734
2735config MMCONF_FAM10H
2736	def_bool y
2737	depends on X86_64 && PCI_MMCONFIG && ACPI
2738
2739config PCI_CNB20LE_QUIRK
2740	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2741	depends on PCI
2742	help
2743	  Read the PCI windows out of the CNB20LE host bridge. This allows
2744	  PCI hotplug to work on systems with the CNB20LE chipset which do
2745	  not have ACPI.
2746
2747	  There's no public spec for this chipset, and this functionality
2748	  is known to be incomplete.
2749
2750	  You should say N unless you know you need this.
2751
2752config ISA_BUS
2753	bool "ISA bus support on modern systems" if EXPERT
2754	help
2755	  Expose ISA bus device drivers and options available for selection and
2756	  configuration. Enable this option if your target machine has an ISA
2757	  bus. ISA is an older system, displaced by PCI and newer bus
2758	  architectures -- if your target machine is modern, it probably does
2759	  not have an ISA bus.
2760
2761	  If unsure, say N.
2762
2763# x86_64 have no ISA slots, but can have ISA-style DMA.
2764config ISA_DMA_API
2765	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2766	default y
2767	help
2768	  Enables ISA-style DMA support for devices requiring such controllers.
2769	  If unsure, say Y.
2770
2771if X86_32
2772
2773config ISA
2774	bool "ISA support"
2775	help
2776	  Find out whether you have ISA slots on your motherboard.  ISA is the
2777	  name of a bus system, i.e. the way the CPU talks to the other stuff
2778	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2779	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2780	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2781
2782config SCx200
2783	tristate "NatSemi SCx200 support"
2784	help
2785	  This provides basic support for National Semiconductor's
2786	  (now AMD's) Geode processors.  The driver probes for the
2787	  PCI-IDs of several on-chip devices, so its a good dependency
2788	  for other scx200_* drivers.
2789
2790	  If compiled as a module, the driver is named scx200.
2791
2792config SCx200HR_TIMER
2793	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2794	depends on SCx200
2795	default y
2796	help
2797	  This driver provides a clocksource built upon the on-chip
2798	  27MHz high-resolution timer.  Its also a workaround for
2799	  NSC Geode SC-1100's buggy TSC, which loses time when the
2800	  processor goes idle (as is done by the scheduler).  The
2801	  other workaround is idle=poll boot option.
2802
2803config OLPC
2804	bool "One Laptop Per Child support"
2805	depends on !X86_PAE
2806	select GPIOLIB
2807	select OF
2808	select OF_PROMTREE
2809	select IRQ_DOMAIN
2810	select OLPC_EC
2811	help
2812	  Add support for detecting the unique features of the OLPC
2813	  XO hardware.
2814
2815config OLPC_XO1_PM
2816	bool "OLPC XO-1 Power Management"
2817	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2818	help
2819	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2820
2821config OLPC_XO1_RTC
2822	bool "OLPC XO-1 Real Time Clock"
2823	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2824	help
2825	  Add support for the XO-1 real time clock, which can be used as a
2826	  programmable wakeup source.
2827
2828config OLPC_XO1_SCI
2829	bool "OLPC XO-1 SCI extras"
2830	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2831	depends on INPUT=y
2832	select POWER_SUPPLY
2833	help
2834	  Add support for SCI-based features of the OLPC XO-1 laptop:
2835	   - EC-driven system wakeups
2836	   - Power button
2837	   - Ebook switch
2838	   - Lid switch
2839	   - AC adapter status updates
2840	   - Battery status updates
2841
2842config OLPC_XO15_SCI
2843	bool "OLPC XO-1.5 SCI extras"
2844	depends on OLPC && ACPI
2845	select POWER_SUPPLY
2846	help
2847	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2848	   - EC-driven system wakeups
2849	   - AC adapter status updates
2850	   - Battery status updates
2851
2852config ALIX
2853	bool "PCEngines ALIX System Support (LED setup)"
2854	select GPIOLIB
2855	help
2856	  This option enables system support for the PCEngines ALIX.
2857	  At present this just sets up LEDs for GPIO control on
2858	  ALIX2/3/6 boards.  However, other system specific setup should
2859	  get added here.
2860
2861	  Note: You must still enable the drivers for GPIO and LED support
2862	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2863
2864	  Note: You have to set alix.force=1 for boards with Award BIOS.
2865
2866config NET5501
2867	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2868	select GPIOLIB
2869	help
2870	  This option enables system support for the Soekris Engineering net5501.
2871
2872config GEOS
2873	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2874	select GPIOLIB
2875	depends on DMI
2876	help
2877	  This option enables system support for the Traverse Technologies GEOS.
2878
2879config TS5500
2880	bool "Technologic Systems TS-5500 platform support"
2881	depends on MELAN
2882	select CHECK_SIGNATURE
2883	select NEW_LEDS
2884	select LEDS_CLASS
2885	help
2886	  This option enables system support for the Technologic Systems TS-5500.
2887
2888endif # X86_32
2889
2890config AMD_NB
2891	def_bool y
2892	depends on CPU_SUP_AMD && PCI
2893
2894config X86_SYSFB
2895	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2896	help
2897	  Firmwares often provide initial graphics framebuffers so the BIOS,
2898	  bootloader or kernel can show basic video-output during boot for
2899	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2900	  Extensions and EFI-framebuffers for this, which are mostly limited
2901	  to x86.
2902	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2903	  framebuffers so the new generic system-framebuffer drivers can be
2904	  used on x86. If the framebuffer is not compatible with the generic
2905	  modes, it is advertised as fallback platform framebuffer so legacy
2906	  drivers like efifb, vesafb and uvesafb can pick it up.
2907	  If this option is not selected, all system framebuffers are always
2908	  marked as fallback platform framebuffers as usual.
2909
2910	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2911	  not be able to pick up generic system framebuffers if this option
2912	  is selected. You are highly encouraged to enable simplefb as
2913	  replacement if you select this option. simplefb can correctly deal
2914	  with generic system framebuffers. But you should still keep vesafb
2915	  and others enabled as fallback if a system framebuffer is
2916	  incompatible with simplefb.
2917
2918	  If unsure, say Y.
2919
2920endmenu
2921
2922
2923menu "Binary Emulations"
2924
2925config IA32_EMULATION
2926	bool "IA32 Emulation"
2927	depends on X86_64
2928	select ARCH_WANT_OLD_COMPAT_IPC
2929	select BINFMT_ELF
2930	select COMPAT_BINFMT_ELF
2931	select COMPAT_OLD_SIGACTION
2932	help
2933	  Include code to run legacy 32-bit programs under a
2934	  64-bit kernel. You should likely turn this on, unless you're
2935	  100% sure that you don't have any 32-bit programs left.
2936
2937config IA32_AOUT
2938	tristate "IA32 a.out support"
2939	depends on IA32_EMULATION
2940	depends on BROKEN
2941	help
2942	  Support old a.out binaries in the 32bit emulation.
2943
2944config X86_X32
2945	bool "x32 ABI for 64-bit mode"
2946	depends on X86_64
2947	# llvm-objcopy does not convert x86_64 .note.gnu.property or
2948	# compressed debug sections to x86_x32 properly:
2949	# https://github.com/ClangBuiltLinux/linux/issues/514
2950	# https://github.com/ClangBuiltLinux/linux/issues/1141
2951	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
2952	help
2953	  Include code to run binaries for the x32 native 32-bit ABI
2954	  for 64-bit processors.  An x32 process gets access to the
2955	  full 64-bit register file and wide data path while leaving
2956	  pointers at 32 bits for smaller memory footprint.
2957
2958	  You will need a recent binutils (2.22 or later) with
2959	  elf32_x86_64 support enabled to compile a kernel with this
2960	  option set.
2961
2962config COMPAT_32
2963	def_bool y
2964	depends on IA32_EMULATION || X86_32
2965	select HAVE_UID16
2966	select OLD_SIGSUSPEND3
2967
2968config COMPAT
2969	def_bool y
2970	depends on IA32_EMULATION || X86_X32
2971
2972if COMPAT
2973config COMPAT_FOR_U64_ALIGNMENT
2974	def_bool y
2975
2976config SYSVIPC_COMPAT
2977	def_bool y
2978	depends on SYSVIPC
2979endif
2980
2981endmenu
2982
2983
2984config HAVE_ATOMIC_IOMAP
2985	def_bool y
2986	depends on X86_32
2987
2988source "drivers/firmware/Kconfig"
2989
2990source "arch/x86/kvm/Kconfig"
2991
2992source "arch/x86/Kconfig.assembler"
2993