xref: /linux/arch/x86/Kconfig (revision 6a34dfa15d6edf7e78b8118d862d2db0889cf669)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select GENERIC_VDSO_32
18	select HAVE_DEBUG_STACKOVERFLOW
19	select KMAP_LOCAL
20	select MODULES_USE_ELF_REL
21	select OLD_SIGACTION
22	select ARCH_SPLIT_ARG64
23
24config X86_64
25	def_bool y
26	depends on 64BIT
27	# Options that are inherently 64-bit kernel only:
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_SUPPORTS_PER_VMA_LOCK
31	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
32	select HAVE_ARCH_SOFT_DIRTY
33	select MODULES_USE_ELF_RELA
34	select NEED_DMA_MAP_STATE
35	select SWIOTLB
36	select ARCH_HAS_ELFCORE_COMPAT
37	select ZONE_DMA32
38	select EXECMEM if DYNAMIC_FTRACE
39
40config FORCE_DYNAMIC_FTRACE
41	def_bool y
42	depends on X86_32
43	depends on FUNCTION_TRACER
44	select DYNAMIC_FTRACE
45	help
46	  We keep the static function tracing (!DYNAMIC_FTRACE) around
47	  in order to test the non static function tracing in the
48	  generic code, as other architectures still use it. But we
49	  only need to keep it around for x86_64. No need to keep it
50	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
51#
52# Arch settings
53#
54# ( Note that options that are marked 'if X86_64' could in principle be
55#   ported to 32-bit as well. )
56#
57config X86
58	def_bool y
59	#
60	# Note: keep this list sorted alphabetically
61	#
62	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
63	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
64	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
65	select ARCH_32BIT_OFF_T			if X86_32
66	select ARCH_CLOCKSOURCE_INIT
67	select ARCH_CONFIGURES_CPU_MITIGATIONS
68	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
69	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
70	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
71	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
72	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
73	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
74	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
75	select ARCH_HAS_CACHE_LINE_SIZE
76	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
77	select ARCH_HAS_CPU_FINALIZE_INIT
78	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
79	select ARCH_HAS_CURRENT_STACK_POINTER
80	select ARCH_HAS_DEBUG_VIRTUAL
81	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
82	select ARCH_HAS_DEVMEM_IS_ALLOWED
83	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
84	select ARCH_HAS_EARLY_DEBUG		if KGDB
85	select ARCH_HAS_ELF_RANDOMIZE
86	select ARCH_HAS_EXECMEM_ROX		if X86_64
87	select ARCH_HAS_FAST_MULTIPLIER
88	select ARCH_HAS_FORTIFY_SOURCE
89	select ARCH_HAS_GCOV_PROFILE_ALL
90	select ARCH_HAS_KCOV			if X86_64
91	select ARCH_HAS_KERNEL_FPU_SUPPORT
92	select ARCH_HAS_MEM_ENCRYPT
93	select ARCH_HAS_MEMBARRIER_SYNC_CORE
94	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
95	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
96	select ARCH_HAS_PMEM_API		if X86_64
97	select ARCH_HAS_PREEMPT_LAZY
98	select ARCH_HAS_PTE_DEVMAP		if X86_64
99	select ARCH_HAS_PTE_SPECIAL
100	select ARCH_HAS_HW_PTE_YOUNG
101	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
102	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
103	select ARCH_HAS_COPY_MC			if X86_64
104	select ARCH_HAS_SET_MEMORY
105	select ARCH_HAS_SET_DIRECT_MAP
106	select ARCH_HAS_STRICT_KERNEL_RWX
107	select ARCH_HAS_STRICT_MODULE_RWX
108	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
109	select ARCH_HAS_SYSCALL_WRAPPER
110	select ARCH_HAS_UBSAN
111	select ARCH_HAS_DEBUG_WX
112	select ARCH_HAS_ZONE_DMA_SET if EXPERT
113	select ARCH_HAVE_NMI_SAFE_CMPXCHG
114	select ARCH_HAVE_EXTRA_ELF_NOTES
115	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
116	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
117	select ARCH_MIGHT_HAVE_PC_PARPORT
118	select ARCH_MIGHT_HAVE_PC_SERIO
119	select ARCH_STACKWALK
120	select ARCH_SUPPORTS_ACPI
121	select ARCH_SUPPORTS_ATOMIC_RMW
122	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
123	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
124	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
125	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
126	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
127	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
128	select ARCH_SUPPORTS_LTO_CLANG
129	select ARCH_SUPPORTS_LTO_CLANG_THIN
130	select ARCH_SUPPORTS_RT
131	select ARCH_SUPPORTS_AUTOFDO_CLANG
132	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
133	select ARCH_USE_BUILTIN_BSWAP
134	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CMPXCHG64
135	select ARCH_USE_MEMTEST
136	select ARCH_USE_QUEUED_RWLOCKS
137	select ARCH_USE_QUEUED_SPINLOCKS
138	select ARCH_USE_SYM_ANNOTATIONS
139	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
140	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
141	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
142	select ARCH_WANTS_NO_INSTR
143	select ARCH_WANT_GENERAL_HUGETLB
144	select ARCH_WANT_HUGE_PMD_SHARE
145	select ARCH_WANT_LD_ORPHAN_WARN
146	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
147	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
148	select ARCH_WANTS_THP_SWAP		if X86_64
149	select ARCH_HAS_PARANOID_L1D_FLUSH
150	select BUILDTIME_TABLE_SORT
151	select CLKEVT_I8253
152	select CLOCKSOURCE_WATCHDOG
153	# Word-size accesses may read uninitialized data past the trailing \0
154	# in strings and cause false KMSAN reports.
155	select DCACHE_WORD_ACCESS		if !KMSAN
156	select DYNAMIC_SIGFRAME
157	select EDAC_ATOMIC_SCRUB
158	select EDAC_SUPPORT
159	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
160	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
161	select GENERIC_CLOCKEVENTS_MIN_ADJUST
162	select GENERIC_CMOS_UPDATE
163	select GENERIC_CPU_AUTOPROBE
164	select GENERIC_CPU_DEVICES
165	select GENERIC_CPU_VULNERABILITIES
166	select GENERIC_EARLY_IOREMAP
167	select GENERIC_ENTRY
168	select GENERIC_IOMAP
169	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
170	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
171	select GENERIC_IRQ_MIGRATION		if SMP
172	select GENERIC_IRQ_PROBE
173	select GENERIC_IRQ_RESERVATION_MODE
174	select GENERIC_IRQ_SHOW
175	select GENERIC_PENDING_IRQ		if SMP
176	select GENERIC_PTDUMP
177	select GENERIC_SMP_IDLE_THREAD
178	select GENERIC_TIME_VSYSCALL
179	select GENERIC_GETTIMEOFDAY
180	select GENERIC_VDSO_TIME_NS
181	select GENERIC_VDSO_OVERFLOW_PROTECT
182	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
183	select HARDIRQS_SW_RESEND
184	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
185	select HAS_IOPORT
186	select HAVE_ACPI_APEI			if ACPI
187	select HAVE_ACPI_APEI_NMI		if ACPI
188	select HAVE_ALIGNED_STRUCT_PAGE
189	select HAVE_ARCH_AUDITSYSCALL
190	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
191	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
192	select HAVE_ARCH_JUMP_LABEL
193	select HAVE_ARCH_JUMP_LABEL_RELATIVE
194	select HAVE_ARCH_KASAN			if X86_64
195	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
196	select HAVE_ARCH_KFENCE
197	select HAVE_ARCH_KMSAN			if X86_64
198	select HAVE_ARCH_KGDB
199	select HAVE_ARCH_MMAP_RND_BITS		if MMU
200	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
201	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
202	select HAVE_ARCH_PREL32_RELOCATIONS
203	select HAVE_ARCH_SECCOMP_FILTER
204	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
205	select HAVE_ARCH_STACKLEAK
206	select HAVE_ARCH_TRACEHOOK
207	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
208	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
209	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
210	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
211	select HAVE_ARCH_VMAP_STACK		if X86_64
212	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
213	select HAVE_ARCH_WITHIN_STACK_FRAMES
214	select HAVE_ASM_MODVERSIONS
215	select HAVE_CMPXCHG_DOUBLE
216	select HAVE_CMPXCHG_LOCAL
217	select HAVE_CONTEXT_TRACKING_USER		if X86_64
218	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
219	select HAVE_C_RECORDMCOUNT
220	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
221	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
222	select HAVE_BUILDTIME_MCOUNT_SORT
223	select HAVE_DEBUG_KMEMLEAK
224	select HAVE_DMA_CONTIGUOUS
225	select HAVE_DYNAMIC_FTRACE
226	select HAVE_DYNAMIC_FTRACE_WITH_REGS
227	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
228	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
229	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
230	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
231	select HAVE_EBPF_JIT
232	select HAVE_EFFICIENT_UNALIGNED_ACCESS
233	select HAVE_EISA
234	select HAVE_EXIT_THREAD
235	select HAVE_GUP_FAST
236	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
237	select HAVE_FTRACE_MCOUNT_RECORD
238	select HAVE_FUNCTION_GRAPH_RETVAL	if HAVE_FUNCTION_GRAPH_TRACER
239	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
240	select HAVE_FUNCTION_TRACER
241	select HAVE_GCC_PLUGINS
242	select HAVE_HW_BREAKPOINT
243	select HAVE_IOREMAP_PROT
244	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
245	select HAVE_IRQ_TIME_ACCOUNTING
246	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
247	select HAVE_KERNEL_BZIP2
248	select HAVE_KERNEL_GZIP
249	select HAVE_KERNEL_LZ4
250	select HAVE_KERNEL_LZMA
251	select HAVE_KERNEL_LZO
252	select HAVE_KERNEL_XZ
253	select HAVE_KERNEL_ZSTD
254	select HAVE_KPROBES
255	select HAVE_KPROBES_ON_FTRACE
256	select HAVE_FUNCTION_ERROR_INJECTION
257	select HAVE_KRETPROBES
258	select HAVE_RETHOOK
259	select HAVE_LIVEPATCH			if X86_64
260	select HAVE_MIXED_BREAKPOINTS_REGS
261	select HAVE_MOD_ARCH_SPECIFIC
262	select HAVE_MOVE_PMD
263	select HAVE_MOVE_PUD
264	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
265	select HAVE_NMI
266	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
267	select HAVE_OBJTOOL			if X86_64
268	select HAVE_OPTPROBES
269	select HAVE_PAGE_SIZE_4KB
270	select HAVE_PCSPKR_PLATFORM
271	select HAVE_PERF_EVENTS
272	select HAVE_PERF_EVENTS_NMI
273	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
274	select HAVE_PCI
275	select HAVE_PERF_REGS
276	select HAVE_PERF_USER_STACK_DUMP
277	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
278	select MMU_GATHER_MERGE_VMAS
279	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
280	select HAVE_REGS_AND_STACK_ACCESS_API
281	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
282	select HAVE_FUNCTION_ARG_ACCESS_API
283	select HAVE_SETUP_PER_CPU_AREA
284	select HAVE_SOFTIRQ_ON_OWN_STACK
285	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
286	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
287	select HAVE_STATIC_CALL
288	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
289	select HAVE_PREEMPT_DYNAMIC_CALL
290	select HAVE_RSEQ
291	select HAVE_RUST			if X86_64
292	select HAVE_SYSCALL_TRACEPOINTS
293	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
294	select HAVE_UNSTABLE_SCHED_CLOCK
295	select HAVE_USER_RETURN_NOTIFIER
296	select HAVE_GENERIC_VDSO
297	select VDSO_GETRANDOM			if X86_64
298	select HOTPLUG_PARALLEL			if SMP && X86_64
299	select HOTPLUG_SMT			if SMP
300	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
301	select IRQ_FORCED_THREADING
302	select LOCK_MM_AND_FIND_VMA
303	select NEED_PER_CPU_EMBED_FIRST_CHUNK
304	select NEED_PER_CPU_PAGE_FIRST_CHUNK
305	select NEED_SG_DMA_LENGTH
306	select NUMA_MEMBLKS			if NUMA
307	select PCI_DOMAINS			if PCI
308	select PCI_LOCKLESS_CONFIG		if PCI
309	select PERF_EVENTS
310	select RTC_LIB
311	select RTC_MC146818_LIB
312	select SPARSE_IRQ
313	select SYSCTL_EXCEPTION_TRACE
314	select THREAD_INFO_IN_TASK
315	select TRACE_IRQFLAGS_SUPPORT
316	select TRACE_IRQFLAGS_NMI_SUPPORT
317	select USER_STACKTRACE_SUPPORT
318	select HAVE_ARCH_KCSAN			if X86_64
319	select PROC_PID_ARCH_STATUS		if PROC_FS
320	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
321	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
322	select FUNCTION_ALIGNMENT_4B
323	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
324	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
325
326config INSTRUCTION_DECODER
327	def_bool y
328	depends on KPROBES || PERF_EVENTS || UPROBES
329
330config OUTPUT_FORMAT
331	string
332	default "elf32-i386" if X86_32
333	default "elf64-x86-64" if X86_64
334
335config LOCKDEP_SUPPORT
336	def_bool y
337
338config STACKTRACE_SUPPORT
339	def_bool y
340
341config MMU
342	def_bool y
343
344config ARCH_MMAP_RND_BITS_MIN
345	default 28 if 64BIT
346	default 8
347
348config ARCH_MMAP_RND_BITS_MAX
349	default 32 if 64BIT
350	default 16
351
352config ARCH_MMAP_RND_COMPAT_BITS_MIN
353	default 8
354
355config ARCH_MMAP_RND_COMPAT_BITS_MAX
356	default 16
357
358config SBUS
359	bool
360
361config GENERIC_ISA_DMA
362	def_bool y
363	depends on ISA_DMA_API
364
365config GENERIC_CSUM
366	bool
367	default y if KMSAN || KASAN
368
369config GENERIC_BUG
370	def_bool y
371	depends on BUG
372	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
373
374config GENERIC_BUG_RELATIVE_POINTERS
375	bool
376
377config ARCH_MAY_HAVE_PC_FDC
378	def_bool y
379	depends on ISA_DMA_API
380
381config GENERIC_CALIBRATE_DELAY
382	def_bool y
383
384config ARCH_HAS_CPU_RELAX
385	def_bool y
386
387config ARCH_HIBERNATION_POSSIBLE
388	def_bool y
389
390config ARCH_SUSPEND_POSSIBLE
391	def_bool y
392
393config AUDIT_ARCH
394	def_bool y if X86_64
395
396config KASAN_SHADOW_OFFSET
397	hex
398	depends on KASAN
399	default 0xdffffc0000000000
400
401config HAVE_INTEL_TXT
402	def_bool y
403	depends on INTEL_IOMMU && ACPI
404
405config X86_64_SMP
406	def_bool y
407	depends on X86_64 && SMP
408
409config ARCH_SUPPORTS_UPROBES
410	def_bool y
411
412config FIX_EARLYCON_MEM
413	def_bool y
414
415config DYNAMIC_PHYSICAL_MASK
416	bool
417
418config PGTABLE_LEVELS
419	int
420	default 5 if X86_5LEVEL
421	default 4 if X86_64
422	default 3 if X86_PAE
423	default 2
424
425config CC_HAS_SANE_STACKPROTECTOR
426	bool
427	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
428	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
429	help
430	  We have to make sure stack protector is unconditionally disabled if
431	  the compiler produces broken code or if it does not let us control
432	  the segment on 32-bit kernels.
433
434menu "Processor type and features"
435
436config SMP
437	bool "Symmetric multi-processing support"
438	help
439	  This enables support for systems with more than one CPU. If you have
440	  a system with only one CPU, say N. If you have a system with more
441	  than one CPU, say Y.
442
443	  If you say N here, the kernel will run on uni- and multiprocessor
444	  machines, but will use only one CPU of a multiprocessor machine. If
445	  you say Y here, the kernel will run on many, but not all,
446	  uniprocessor machines. On a uniprocessor machine, the kernel
447	  will run faster if you say N here.
448
449	  Note that if you say Y here and choose architecture "586" or
450	  "Pentium" under "Processor family", the kernel will not work on 486
451	  architectures. Similarly, multiprocessor kernels for the "PPro"
452	  architecture may not work on all Pentium based boards.
453
454	  People using multiprocessor machines who say Y here should also say
455	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
456	  Management" code will be disabled if you say Y here.
457
458	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
459	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
460	  <http://www.tldp.org/docs.html#howto>.
461
462	  If you don't know what to do here, say N.
463
464config X86_X2APIC
465	bool "Support x2apic"
466	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
467	help
468	  This enables x2apic support on CPUs that have this feature.
469
470	  This allows 32-bit apic IDs (so it can support very large systems),
471	  and accesses the local apic via MSRs not via mmio.
472
473	  Some Intel systems circa 2022 and later are locked into x2APIC mode
474	  and can not fall back to the legacy APIC modes if SGX or TDX are
475	  enabled in the BIOS. They will boot with very reduced functionality
476	  without enabling this option.
477
478	  If you don't know what to do here, say N.
479
480config X86_POSTED_MSI
481	bool "Enable MSI and MSI-x delivery by posted interrupts"
482	depends on X86_64 && IRQ_REMAP
483	help
484	  This enables MSIs that are under interrupt remapping to be delivered as
485	  posted interrupts to the host kernel. Interrupt throughput can
486	  potentially be improved by coalescing CPU notifications during high
487	  frequency bursts.
488
489	  If you don't know what to do here, say N.
490
491config X86_MPPARSE
492	bool "Enable MPS table" if ACPI
493	default y
494	depends on X86_LOCAL_APIC
495	help
496	  For old smp systems that do not have proper acpi support. Newer systems
497	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
498
499config X86_CPU_RESCTRL
500	bool "x86 CPU resource control support"
501	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
502	select KERNFS
503	select PROC_CPU_RESCTRL		if PROC_FS
504	help
505	  Enable x86 CPU resource control support.
506
507	  Provide support for the allocation and monitoring of system resources
508	  usage by the CPU.
509
510	  Intel calls this Intel Resource Director Technology
511	  (Intel(R) RDT). More information about RDT can be found in the
512	  Intel x86 Architecture Software Developer Manual.
513
514	  AMD calls this AMD Platform Quality of Service (AMD QoS).
515	  More information about AMD QoS can be found in the AMD64 Technology
516	  Platform Quality of Service Extensions manual.
517
518	  Say N if unsure.
519
520config X86_FRED
521	bool "Flexible Return and Event Delivery"
522	depends on X86_64
523	help
524	  When enabled, try to use Flexible Return and Event Delivery
525	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
526	  ring transitions and exception/interrupt handling if the
527	  system supports it.
528
529config X86_BIGSMP
530	bool "Support for big SMP systems with more than 8 CPUs"
531	depends on SMP && X86_32
532	help
533	  This option is needed for the systems that have more than 8 CPUs.
534
535config X86_EXTENDED_PLATFORM
536	bool "Support for extended (non-PC) x86 platforms"
537	default y
538	help
539	  If you disable this option then the kernel will only support
540	  standard PC platforms. (which covers the vast majority of
541	  systems out there.)
542
543	  If you enable this option then you'll be able to select support
544	  for the following non-PC x86 platforms, depending on the value of
545	  CONFIG_64BIT.
546
547	  32-bit platforms (CONFIG_64BIT=n):
548		Goldfish (Android emulator)
549		AMD Elan
550		RDC R-321x SoC
551		SGI 320/540 (Visual Workstation)
552		STA2X11-based (e.g. Northville)
553		Moorestown MID devices
554
555	  64-bit platforms (CONFIG_64BIT=y):
556		Numascale NumaChip
557		ScaleMP vSMP
558		SGI Ultraviolet
559
560	  If you have one of these systems, or if you want to build a
561	  generic distribution kernel, say Y here - otherwise say N.
562
563# This is an alphabetically sorted list of 64 bit extended platforms
564# Please maintain the alphabetic order if and when there are additions
565config X86_NUMACHIP
566	bool "Numascale NumaChip"
567	depends on X86_64
568	depends on X86_EXTENDED_PLATFORM
569	depends on NUMA
570	depends on SMP
571	depends on X86_X2APIC
572	depends on PCI_MMCONFIG
573	help
574	  Adds support for Numascale NumaChip large-SMP systems. Needed to
575	  enable more than ~168 cores.
576	  If you don't have one of these, you should say N here.
577
578config X86_VSMP
579	bool "ScaleMP vSMP"
580	select HYPERVISOR_GUEST
581	select PARAVIRT
582	depends on X86_64 && PCI
583	depends on X86_EXTENDED_PLATFORM
584	depends on SMP
585	help
586	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
587	  supposed to run on these EM64T-based machines.  Only choose this option
588	  if you have one of these machines.
589
590config X86_UV
591	bool "SGI Ultraviolet"
592	depends on X86_64
593	depends on X86_EXTENDED_PLATFORM
594	depends on NUMA
595	depends on EFI
596	depends on KEXEC_CORE
597	depends on X86_X2APIC
598	depends on PCI
599	help
600	  This option is needed in order to support SGI Ultraviolet systems.
601	  If you don't have one of these, you should say N here.
602
603# Following is an alphabetically sorted list of 32 bit extended platforms
604# Please maintain the alphabetic order if and when there are additions
605
606config X86_GOLDFISH
607	bool "Goldfish (Virtual Platform)"
608	depends on X86_EXTENDED_PLATFORM
609	help
610	  Enable support for the Goldfish virtual platform used primarily
611	  for Android development. Unless you are building for the Android
612	  Goldfish emulator say N here.
613
614config X86_INTEL_CE
615	bool "CE4100 TV platform"
616	depends on PCI
617	depends on PCI_GODIRECT
618	depends on X86_IO_APIC
619	depends on X86_32
620	depends on X86_EXTENDED_PLATFORM
621	select X86_REBOOTFIXUPS
622	select OF
623	select OF_EARLY_FLATTREE
624	help
625	  Select for the Intel CE media processor (CE4100) SOC.
626	  This option compiles in support for the CE4100 SOC for settop
627	  boxes and media devices.
628
629config X86_INTEL_MID
630	bool "Intel MID platform support"
631	depends on X86_EXTENDED_PLATFORM
632	depends on X86_PLATFORM_DEVICES
633	depends on PCI
634	depends on X86_64 || (PCI_GOANY && X86_32)
635	depends on X86_IO_APIC
636	select I2C
637	select DW_APB_TIMER
638	select INTEL_SCU_PCI
639	help
640	  Select to build a kernel capable of supporting Intel MID (Mobile
641	  Internet Device) platform systems which do not have the PCI legacy
642	  interfaces. If you are building for a PC class system say N here.
643
644	  Intel MID platforms are based on an Intel processor and chipset which
645	  consume less power than most of the x86 derivatives.
646
647config X86_INTEL_QUARK
648	bool "Intel Quark platform support"
649	depends on X86_32
650	depends on X86_EXTENDED_PLATFORM
651	depends on X86_PLATFORM_DEVICES
652	depends on X86_TSC
653	depends on PCI
654	depends on PCI_GOANY
655	depends on X86_IO_APIC
656	select IOSF_MBI
657	select INTEL_IMR
658	select COMMON_CLK
659	help
660	  Select to include support for Quark X1000 SoC.
661	  Say Y here if you have a Quark based system such as the Arduino
662	  compatible Intel Galileo.
663
664config X86_INTEL_LPSS
665	bool "Intel Low Power Subsystem Support"
666	depends on X86 && ACPI && PCI
667	select COMMON_CLK
668	select PINCTRL
669	select IOSF_MBI
670	help
671	  Select to build support for Intel Low Power Subsystem such as
672	  found on Intel Lynxpoint PCH. Selecting this option enables
673	  things like clock tree (common clock framework) and pincontrol
674	  which are needed by the LPSS peripheral drivers.
675
676config X86_AMD_PLATFORM_DEVICE
677	bool "AMD ACPI2Platform devices support"
678	depends on ACPI
679	select COMMON_CLK
680	select PINCTRL
681	help
682	  Select to interpret AMD specific ACPI device to platform device
683	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
684	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
685	  implemented under PINCTRL subsystem.
686
687config IOSF_MBI
688	tristate "Intel SoC IOSF Sideband support for SoC platforms"
689	depends on PCI
690	help
691	  This option enables sideband register access support for Intel SoC
692	  platforms. On these platforms the IOSF sideband is used in lieu of
693	  MSR's for some register accesses, mostly but not limited to thermal
694	  and power. Drivers may query the availability of this device to
695	  determine if they need the sideband in order to work on these
696	  platforms. The sideband is available on the following SoC products.
697	  This list is not meant to be exclusive.
698	   - BayTrail
699	   - Braswell
700	   - Quark
701
702	  You should say Y if you are running a kernel on one of these SoC's.
703
704config IOSF_MBI_DEBUG
705	bool "Enable IOSF sideband access through debugfs"
706	depends on IOSF_MBI && DEBUG_FS
707	help
708	  Select this option to expose the IOSF sideband access registers (MCR,
709	  MDR, MCRX) through debugfs to write and read register information from
710	  different units on the SoC. This is most useful for obtaining device
711	  state information for debug and analysis. As this is a general access
712	  mechanism, users of this option would have specific knowledge of the
713	  device they want to access.
714
715	  If you don't require the option or are in doubt, say N.
716
717config X86_RDC321X
718	bool "RDC R-321x SoC"
719	depends on X86_32
720	depends on X86_EXTENDED_PLATFORM
721	select M486
722	select X86_REBOOTFIXUPS
723	help
724	  This option is needed for RDC R-321x system-on-chip, also known
725	  as R-8610-(G).
726	  If you don't have one of these chips, you should say N here.
727
728config X86_32_NON_STANDARD
729	bool "Support non-standard 32-bit SMP architectures"
730	depends on X86_32 && SMP
731	depends on X86_EXTENDED_PLATFORM
732	help
733	  This option compiles in the bigsmp and STA2X11 default
734	  subarchitectures.  It is intended for a generic binary
735	  kernel. If you select them all, kernel will probe it one by
736	  one and will fallback to default.
737
738# Alphabetically sorted list of Non standard 32 bit platforms
739
740config X86_SUPPORTS_MEMORY_FAILURE
741	def_bool y
742	# MCE code calls memory_failure():
743	depends on X86_MCE
744	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
745	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
746	depends on X86_64 || !SPARSEMEM
747	select ARCH_SUPPORTS_MEMORY_FAILURE
748
749config STA2X11
750	bool "STA2X11 Companion Chip Support"
751	depends on X86_32_NON_STANDARD && PCI
752	select SWIOTLB
753	select MFD_STA2X11
754	select GPIOLIB
755	help
756	  This adds support for boards based on the STA2X11 IO-Hub,
757	  a.k.a. "ConneXt". The chip is used in place of the standard
758	  PC chipset, so all "standard" peripherals are missing. If this
759	  option is selected the kernel will still be able to boot on
760	  standard PC machines.
761
762config X86_32_IRIS
763	tristate "Eurobraille/Iris poweroff module"
764	depends on X86_32
765	help
766	  The Iris machines from EuroBraille do not have APM or ACPI support
767	  to shut themselves down properly.  A special I/O sequence is
768	  needed to do so, which is what this module does at
769	  kernel shutdown.
770
771	  This is only for Iris machines from EuroBraille.
772
773	  If unused, say N.
774
775config SCHED_OMIT_FRAME_POINTER
776	def_bool y
777	prompt "Single-depth WCHAN output"
778	depends on X86
779	help
780	  Calculate simpler /proc/<PID>/wchan values. If this option
781	  is disabled then wchan values will recurse back to the
782	  caller function. This provides more accurate wchan values,
783	  at the expense of slightly more scheduling overhead.
784
785	  If in doubt, say "Y".
786
787menuconfig HYPERVISOR_GUEST
788	bool "Linux guest support"
789	help
790	  Say Y here to enable options for running Linux under various hyper-
791	  visors. This option enables basic hypervisor detection and platform
792	  setup.
793
794	  If you say N, all options in this submenu will be skipped and
795	  disabled, and Linux guest support won't be built in.
796
797if HYPERVISOR_GUEST
798
799config PARAVIRT
800	bool "Enable paravirtualization code"
801	depends on HAVE_STATIC_CALL
802	help
803	  This changes the kernel so it can modify itself when it is run
804	  under a hypervisor, potentially improving performance significantly
805	  over full virtualization.  However, when run without a hypervisor
806	  the kernel is theoretically slower and slightly larger.
807
808config PARAVIRT_XXL
809	bool
810
811config PARAVIRT_DEBUG
812	bool "paravirt-ops debugging"
813	depends on PARAVIRT && DEBUG_KERNEL
814	help
815	  Enable to debug paravirt_ops internals.  Specifically, BUG if
816	  a paravirt_op is missing when it is called.
817
818config PARAVIRT_SPINLOCKS
819	bool "Paravirtualization layer for spinlocks"
820	depends on PARAVIRT && SMP
821	help
822	  Paravirtualized spinlocks allow a pvops backend to replace the
823	  spinlock implementation with something virtualization-friendly
824	  (for example, block the virtual CPU rather than spinning).
825
826	  It has a minimal impact on native kernels and gives a nice performance
827	  benefit on paravirtualized KVM / Xen kernels.
828
829	  If you are unsure how to answer this question, answer Y.
830
831config X86_HV_CALLBACK_VECTOR
832	def_bool n
833
834source "arch/x86/xen/Kconfig"
835
836config KVM_GUEST
837	bool "KVM Guest support (including kvmclock)"
838	depends on PARAVIRT
839	select PARAVIRT_CLOCK
840	select ARCH_CPUIDLE_HALTPOLL
841	select X86_HV_CALLBACK_VECTOR
842	default y
843	help
844	  This option enables various optimizations for running under the KVM
845	  hypervisor. It includes a paravirtualized clock, so that instead
846	  of relying on a PIT (or probably other) emulation by the
847	  underlying device model, the host provides the guest with
848	  timing infrastructure such as time of day, and system time
849
850config ARCH_CPUIDLE_HALTPOLL
851	def_bool n
852	prompt "Disable host haltpoll when loading haltpoll driver"
853	help
854	  If virtualized under KVM, disable host haltpoll.
855
856config PVH
857	bool "Support for running PVH guests"
858	help
859	  This option enables the PVH entry point for guest virtual machines
860	  as specified in the x86/HVM direct boot ABI.
861
862config PARAVIRT_TIME_ACCOUNTING
863	bool "Paravirtual steal time accounting"
864	depends on PARAVIRT
865	help
866	  Select this option to enable fine granularity task steal time
867	  accounting. Time spent executing other tasks in parallel with
868	  the current vCPU is discounted from the vCPU power. To account for
869	  that, there can be a small performance impact.
870
871	  If in doubt, say N here.
872
873config PARAVIRT_CLOCK
874	bool
875
876config JAILHOUSE_GUEST
877	bool "Jailhouse non-root cell support"
878	depends on X86_64 && PCI
879	select X86_PM_TIMER
880	help
881	  This option allows to run Linux as guest in a Jailhouse non-root
882	  cell. You can leave this option disabled if you only want to start
883	  Jailhouse and run Linux afterwards in the root cell.
884
885config ACRN_GUEST
886	bool "ACRN Guest support"
887	depends on X86_64
888	select X86_HV_CALLBACK_VECTOR
889	help
890	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
891	  a flexible, lightweight reference open-source hypervisor, built with
892	  real-time and safety-criticality in mind. It is built for embedded
893	  IOT with small footprint and real-time features. More details can be
894	  found in https://projectacrn.org/.
895
896config INTEL_TDX_GUEST
897	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
898	depends on X86_64 && CPU_SUP_INTEL
899	depends on X86_X2APIC
900	depends on EFI_STUB
901	select ARCH_HAS_CC_PLATFORM
902	select X86_MEM_ENCRYPT
903	select X86_MCE
904	select UNACCEPTED_MEMORY
905	help
906	  Support running as a guest under Intel TDX.  Without this support,
907	  the guest kernel can not boot or run under TDX.
908	  TDX includes memory encryption and integrity capabilities
909	  which protect the confidentiality and integrity of guest
910	  memory contents and CPU state. TDX guests are protected from
911	  some attacks from the VMM.
912
913endif # HYPERVISOR_GUEST
914
915source "arch/x86/Kconfig.cpu"
916
917config HPET_TIMER
918	def_bool X86_64
919	prompt "HPET Timer Support" if X86_32
920	help
921	  Use the IA-PC HPET (High Precision Event Timer) to manage
922	  time in preference to the PIT and RTC, if a HPET is
923	  present.
924	  HPET is the next generation timer replacing legacy 8254s.
925	  The HPET provides a stable time base on SMP
926	  systems, unlike the TSC, but it is more expensive to access,
927	  as it is off-chip.  The interface used is documented
928	  in the HPET spec, revision 1.
929
930	  You can safely choose Y here.  However, HPET will only be
931	  activated if the platform and the BIOS support this feature.
932	  Otherwise the 8254 will be used for timing services.
933
934	  Choose N to continue using the legacy 8254 timer.
935
936config HPET_EMULATE_RTC
937	def_bool y
938	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
939
940# Mark as expert because too many people got it wrong.
941# The code disables itself when not needed.
942config DMI
943	default y
944	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
945	bool "Enable DMI scanning" if EXPERT
946	help
947	  Enabled scanning of DMI to identify machine quirks. Say Y
948	  here unless you have verified that your setup is not
949	  affected by entries in the DMI blacklist. Required by PNP
950	  BIOS code.
951
952config GART_IOMMU
953	bool "Old AMD GART IOMMU support"
954	select IOMMU_HELPER
955	select SWIOTLB
956	depends on X86_64 && PCI && AMD_NB
957	help
958	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
959	  GART based hardware IOMMUs.
960
961	  The GART supports full DMA access for devices with 32-bit access
962	  limitations, on systems with more than 3 GB. This is usually needed
963	  for USB, sound, many IDE/SATA chipsets and some other devices.
964
965	  Newer systems typically have a modern AMD IOMMU, supported via
966	  the CONFIG_AMD_IOMMU=y config option.
967
968	  In normal configurations this driver is only active when needed:
969	  there's more than 3 GB of memory and the system contains a
970	  32-bit limited device.
971
972	  If unsure, say Y.
973
974config BOOT_VESA_SUPPORT
975	bool
976	help
977	  If true, at least one selected framebuffer driver can take advantage
978	  of VESA video modes set at an early boot stage via the vga= parameter.
979
980config MAXSMP
981	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
982	depends on X86_64 && SMP && DEBUG_KERNEL
983	select CPUMASK_OFFSTACK
984	help
985	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
986	  If unsure, say N.
987
988#
989# The maximum number of CPUs supported:
990#
991# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
992# and which can be configured interactively in the
993# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
994#
995# The ranges are different on 32-bit and 64-bit kernels, depending on
996# hardware capabilities and scalability features of the kernel.
997#
998# ( If MAXSMP is enabled we just use the highest possible value and disable
999#   interactive configuration. )
1000#
1001
1002config NR_CPUS_RANGE_BEGIN
1003	int
1004	default NR_CPUS_RANGE_END if MAXSMP
1005	default    1 if !SMP
1006	default    2
1007
1008config NR_CPUS_RANGE_END
1009	int
1010	depends on X86_32
1011	default   64 if  SMP &&  X86_BIGSMP
1012	default    8 if  SMP && !X86_BIGSMP
1013	default    1 if !SMP
1014
1015config NR_CPUS_RANGE_END
1016	int
1017	depends on X86_64
1018	default 8192 if  SMP && CPUMASK_OFFSTACK
1019	default  512 if  SMP && !CPUMASK_OFFSTACK
1020	default    1 if !SMP
1021
1022config NR_CPUS_DEFAULT
1023	int
1024	depends on X86_32
1025	default   32 if  X86_BIGSMP
1026	default    8 if  SMP
1027	default    1 if !SMP
1028
1029config NR_CPUS_DEFAULT
1030	int
1031	depends on X86_64
1032	default 8192 if  MAXSMP
1033	default   64 if  SMP
1034	default    1 if !SMP
1035
1036config NR_CPUS
1037	int "Maximum number of CPUs" if SMP && !MAXSMP
1038	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1039	default NR_CPUS_DEFAULT
1040	help
1041	  This allows you to specify the maximum number of CPUs which this
1042	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1043	  supported value is 8192, otherwise the maximum value is 512.  The
1044	  minimum value which makes sense is 2.
1045
1046	  This is purely to save memory: each supported CPU adds about 8KB
1047	  to the kernel image.
1048
1049config SCHED_CLUSTER
1050	bool "Cluster scheduler support"
1051	depends on SMP
1052	default y
1053	help
1054	  Cluster scheduler support improves the CPU scheduler's decision
1055	  making when dealing with machines that have clusters of CPUs.
1056	  Cluster usually means a couple of CPUs which are placed closely
1057	  by sharing mid-level caches, last-level cache tags or internal
1058	  busses.
1059
1060config SCHED_SMT
1061	def_bool y if SMP
1062
1063config SCHED_MC
1064	def_bool y
1065	prompt "Multi-core scheduler support"
1066	depends on SMP
1067	help
1068	  Multi-core scheduler support improves the CPU scheduler's decision
1069	  making when dealing with multi-core CPU chips at a cost of slightly
1070	  increased overhead in some places. If unsure say N here.
1071
1072config SCHED_MC_PRIO
1073	bool "CPU core priorities scheduler support"
1074	depends on SCHED_MC
1075	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1076	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1077	select CPU_FREQ
1078	default y
1079	help
1080	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1081	  core ordering determined at manufacturing time, which allows
1082	  certain cores to reach higher turbo frequencies (when running
1083	  single threaded workloads) than others.
1084
1085	  Enabling this kernel feature teaches the scheduler about
1086	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1087	  scheduler's CPU selection logic accordingly, so that higher
1088	  overall system performance can be achieved.
1089
1090	  This feature will have no effect on CPUs without this feature.
1091
1092	  If unsure say Y here.
1093
1094config UP_LATE_INIT
1095	def_bool y
1096	depends on !SMP && X86_LOCAL_APIC
1097
1098config X86_UP_APIC
1099	bool "Local APIC support on uniprocessors" if !PCI_MSI
1100	default PCI_MSI
1101	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1102	help
1103	  A local APIC (Advanced Programmable Interrupt Controller) is an
1104	  integrated interrupt controller in the CPU. If you have a single-CPU
1105	  system which has a processor with a local APIC, you can say Y here to
1106	  enable and use it. If you say Y here even though your machine doesn't
1107	  have a local APIC, then the kernel will still run with no slowdown at
1108	  all. The local APIC supports CPU-generated self-interrupts (timer,
1109	  performance counters), and the NMI watchdog which detects hard
1110	  lockups.
1111
1112config X86_UP_IOAPIC
1113	bool "IO-APIC support on uniprocessors"
1114	depends on X86_UP_APIC
1115	help
1116	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1117	  SMP-capable replacement for PC-style interrupt controllers. Most
1118	  SMP systems and many recent uniprocessor systems have one.
1119
1120	  If you have a single-CPU system with an IO-APIC, you can say Y here
1121	  to use it. If you say Y here even though your machine doesn't have
1122	  an IO-APIC, then the kernel will still run with no slowdown at all.
1123
1124config X86_LOCAL_APIC
1125	def_bool y
1126	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1127	select IRQ_DOMAIN_HIERARCHY
1128
1129config ACPI_MADT_WAKEUP
1130	def_bool y
1131	depends on X86_64
1132	depends on ACPI
1133	depends on SMP
1134	depends on X86_LOCAL_APIC
1135
1136config X86_IO_APIC
1137	def_bool y
1138	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1139
1140config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1141	bool "Reroute for broken boot IRQs"
1142	depends on X86_IO_APIC
1143	help
1144	  This option enables a workaround that fixes a source of
1145	  spurious interrupts. This is recommended when threaded
1146	  interrupt handling is used on systems where the generation of
1147	  superfluous "boot interrupts" cannot be disabled.
1148
1149	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1150	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1151	  kernel does during interrupt handling). On chipsets where this
1152	  boot IRQ generation cannot be disabled, this workaround keeps
1153	  the original IRQ line masked so that only the equivalent "boot
1154	  IRQ" is delivered to the CPUs. The workaround also tells the
1155	  kernel to set up the IRQ handler on the boot IRQ line. In this
1156	  way only one interrupt is delivered to the kernel. Otherwise
1157	  the spurious second interrupt may cause the kernel to bring
1158	  down (vital) interrupt lines.
1159
1160	  Only affects "broken" chipsets. Interrupt sharing may be
1161	  increased on these systems.
1162
1163config X86_MCE
1164	bool "Machine Check / overheating reporting"
1165	select GENERIC_ALLOCATOR
1166	default y
1167	help
1168	  Machine Check support allows the processor to notify the
1169	  kernel if it detects a problem (e.g. overheating, data corruption).
1170	  The action the kernel takes depends on the severity of the problem,
1171	  ranging from warning messages to halting the machine.
1172
1173config X86_MCELOG_LEGACY
1174	bool "Support for deprecated /dev/mcelog character device"
1175	depends on X86_MCE
1176	help
1177	  Enable support for /dev/mcelog which is needed by the old mcelog
1178	  userspace logging daemon. Consider switching to the new generation
1179	  rasdaemon solution.
1180
1181config X86_MCE_INTEL
1182	def_bool y
1183	prompt "Intel MCE features"
1184	depends on X86_MCE && X86_LOCAL_APIC
1185	help
1186	  Additional support for intel specific MCE features such as
1187	  the thermal monitor.
1188
1189config X86_MCE_AMD
1190	def_bool y
1191	prompt "AMD MCE features"
1192	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1193	help
1194	  Additional support for AMD specific MCE features such as
1195	  the DRAM Error Threshold.
1196
1197config X86_ANCIENT_MCE
1198	bool "Support for old Pentium 5 / WinChip machine checks"
1199	depends on X86_32 && X86_MCE
1200	help
1201	  Include support for machine check handling on old Pentium 5 or WinChip
1202	  systems. These typically need to be enabled explicitly on the command
1203	  line.
1204
1205config X86_MCE_THRESHOLD
1206	depends on X86_MCE_AMD || X86_MCE_INTEL
1207	def_bool y
1208
1209config X86_MCE_INJECT
1210	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1211	tristate "Machine check injector support"
1212	help
1213	  Provide support for injecting machine checks for testing purposes.
1214	  If you don't know what a machine check is and you don't do kernel
1215	  QA it is safe to say n.
1216
1217source "arch/x86/events/Kconfig"
1218
1219config X86_LEGACY_VM86
1220	bool "Legacy VM86 support"
1221	depends on X86_32
1222	help
1223	  This option allows user programs to put the CPU into V8086
1224	  mode, which is an 80286-era approximation of 16-bit real mode.
1225
1226	  Some very old versions of X and/or vbetool require this option
1227	  for user mode setting.  Similarly, DOSEMU will use it if
1228	  available to accelerate real mode DOS programs.  However, any
1229	  recent version of DOSEMU, X, or vbetool should be fully
1230	  functional even without kernel VM86 support, as they will all
1231	  fall back to software emulation. Nevertheless, if you are using
1232	  a 16-bit DOS program where 16-bit performance matters, vm86
1233	  mode might be faster than emulation and you might want to
1234	  enable this option.
1235
1236	  Note that any app that works on a 64-bit kernel is unlikely to
1237	  need this option, as 64-bit kernels don't, and can't, support
1238	  V8086 mode. This option is also unrelated to 16-bit protected
1239	  mode and is not needed to run most 16-bit programs under Wine.
1240
1241	  Enabling this option increases the complexity of the kernel
1242	  and slows down exception handling a tiny bit.
1243
1244	  If unsure, say N here.
1245
1246config VM86
1247	bool
1248	default X86_LEGACY_VM86
1249
1250config X86_16BIT
1251	bool "Enable support for 16-bit segments" if EXPERT
1252	default y
1253	depends on MODIFY_LDT_SYSCALL
1254	help
1255	  This option is required by programs like Wine to run 16-bit
1256	  protected mode legacy code on x86 processors.  Disabling
1257	  this option saves about 300 bytes on i386, or around 6K text
1258	  plus 16K runtime memory on x86-64,
1259
1260config X86_ESPFIX32
1261	def_bool y
1262	depends on X86_16BIT && X86_32
1263
1264config X86_ESPFIX64
1265	def_bool y
1266	depends on X86_16BIT && X86_64
1267
1268config X86_VSYSCALL_EMULATION
1269	bool "Enable vsyscall emulation" if EXPERT
1270	default y
1271	depends on X86_64
1272	help
1273	  This enables emulation of the legacy vsyscall page.  Disabling
1274	  it is roughly equivalent to booting with vsyscall=none, except
1275	  that it will also disable the helpful warning if a program
1276	  tries to use a vsyscall.  With this option set to N, offending
1277	  programs will just segfault, citing addresses of the form
1278	  0xffffffffff600?00.
1279
1280	  This option is required by many programs built before 2013, and
1281	  care should be used even with newer programs if set to N.
1282
1283	  Disabling this option saves about 7K of kernel size and
1284	  possibly 4K of additional runtime pagetable memory.
1285
1286config X86_IOPL_IOPERM
1287	bool "IOPERM and IOPL Emulation"
1288	default y
1289	help
1290	  This enables the ioperm() and iopl() syscalls which are necessary
1291	  for legacy applications.
1292
1293	  Legacy IOPL support is an overbroad mechanism which allows user
1294	  space aside of accessing all 65536 I/O ports also to disable
1295	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1296	  capabilities and permission from potentially active security
1297	  modules.
1298
1299	  The emulation restricts the functionality of the syscall to
1300	  only allowing the full range I/O port access, but prevents the
1301	  ability to disable interrupts from user space which would be
1302	  granted if the hardware IOPL mechanism would be used.
1303
1304config TOSHIBA
1305	tristate "Toshiba Laptop support"
1306	depends on X86_32
1307	help
1308	  This adds a driver to safely access the System Management Mode of
1309	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1310	  not work on models with a Phoenix BIOS. The System Management Mode
1311	  is used to set the BIOS and power saving options on Toshiba portables.
1312
1313	  For information on utilities to make use of this driver see the
1314	  Toshiba Linux utilities web site at:
1315	  <http://www.buzzard.org.uk/toshiba/>.
1316
1317	  Say Y if you intend to run this kernel on a Toshiba portable.
1318	  Say N otherwise.
1319
1320config X86_REBOOTFIXUPS
1321	bool "Enable X86 board specific fixups for reboot"
1322	depends on X86_32
1323	help
1324	  This enables chipset and/or board specific fixups to be done
1325	  in order to get reboot to work correctly. This is only needed on
1326	  some combinations of hardware and BIOS. The symptom, for which
1327	  this config is intended, is when reboot ends with a stalled/hung
1328	  system.
1329
1330	  Currently, the only fixup is for the Geode machines using
1331	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1332
1333	  Say Y if you want to enable the fixup. Currently, it's safe to
1334	  enable this option even if you don't need it.
1335	  Say N otherwise.
1336
1337config MICROCODE
1338	def_bool y
1339	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1340
1341config MICROCODE_INITRD32
1342	def_bool y
1343	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1344
1345config MICROCODE_LATE_LOADING
1346	bool "Late microcode loading (DANGEROUS)"
1347	default n
1348	depends on MICROCODE && SMP
1349	help
1350	  Loading microcode late, when the system is up and executing instructions
1351	  is a tricky business and should be avoided if possible. Just the sequence
1352	  of synchronizing all cores and SMT threads is one fragile dance which does
1353	  not guarantee that cores might not softlock after the loading. Therefore,
1354	  use this at your own risk. Late loading taints the kernel unless the
1355	  microcode header indicates that it is safe for late loading via the
1356	  minimal revision check. This minimal revision check can be enforced on
1357	  the kernel command line with "microcode.minrev=Y".
1358
1359config MICROCODE_LATE_FORCE_MINREV
1360	bool "Enforce late microcode loading minimal revision check"
1361	default n
1362	depends on MICROCODE_LATE_LOADING
1363	help
1364	  To prevent that users load microcode late which modifies already
1365	  in use features, newer microcode patches have a minimum revision field
1366	  in the microcode header, which tells the kernel which minimum
1367	  revision must be active in the CPU to safely load that new microcode
1368	  late into the running system. If disabled the check will not
1369	  be enforced but the kernel will be tainted when the minimal
1370	  revision check fails.
1371
1372	  This minimal revision check can also be controlled via the
1373	  "microcode.minrev" parameter on the kernel command line.
1374
1375	  If unsure say Y.
1376
1377config X86_MSR
1378	tristate "/dev/cpu/*/msr - Model-specific register support"
1379	help
1380	  This device gives privileged processes access to the x86
1381	  Model-Specific Registers (MSRs).  It is a character device with
1382	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1383	  MSR accesses are directed to a specific CPU on multi-processor
1384	  systems.
1385
1386config X86_CPUID
1387	tristate "/dev/cpu/*/cpuid - CPU information support"
1388	help
1389	  This device gives processes access to the x86 CPUID instruction to
1390	  be executed on a specific processor.  It is a character device
1391	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1392	  /dev/cpu/31/cpuid.
1393
1394choice
1395	prompt "High Memory Support"
1396	default HIGHMEM4G
1397	depends on X86_32
1398
1399config NOHIGHMEM
1400	bool "off"
1401	help
1402	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1403	  However, the address space of 32-bit x86 processors is only 4
1404	  Gigabytes large. That means that, if you have a large amount of
1405	  physical memory, not all of it can be "permanently mapped" by the
1406	  kernel. The physical memory that's not permanently mapped is called
1407	  "high memory".
1408
1409	  If you are compiling a kernel which will never run on a machine with
1410	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1411	  choice and suitable for most users). This will result in a "3GB/1GB"
1412	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1413	  space and the remaining part of the 4GB virtual memory space is used
1414	  by the kernel to permanently map as much physical memory as
1415	  possible.
1416
1417	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1418	  answer "4GB" here.
1419
1420	  If more than 4 Gigabytes is used then answer "64GB" here. This
1421	  selection turns Intel PAE (Physical Address Extension) mode on.
1422	  PAE implements 3-level paging on IA32 processors. PAE is fully
1423	  supported by Linux, PAE mode is implemented on all recent Intel
1424	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1425	  then the kernel will not boot on CPUs that don't support PAE!
1426
1427	  The actual amount of total physical memory will either be
1428	  auto detected or can be forced by using a kernel command line option
1429	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1430	  your boot loader (lilo or loadlin) about how to pass options to the
1431	  kernel at boot time.)
1432
1433	  If unsure, say "off".
1434
1435config HIGHMEM4G
1436	bool "4GB"
1437	help
1438	  Select this if you have a 32-bit processor and between 1 and 4
1439	  gigabytes of physical RAM.
1440
1441config HIGHMEM64G
1442	bool "64GB"
1443	depends on X86_HAVE_PAE
1444	select X86_PAE
1445	help
1446	  Select this if you have a 32-bit processor and more than 4
1447	  gigabytes of physical RAM.
1448
1449endchoice
1450
1451choice
1452	prompt "Memory split" if EXPERT
1453	default VMSPLIT_3G
1454	depends on X86_32
1455	help
1456	  Select the desired split between kernel and user memory.
1457
1458	  If the address range available to the kernel is less than the
1459	  physical memory installed, the remaining memory will be available
1460	  as "high memory". Accessing high memory is a little more costly
1461	  than low memory, as it needs to be mapped into the kernel first.
1462	  Note that increasing the kernel address space limits the range
1463	  available to user programs, making the address space there
1464	  tighter.  Selecting anything other than the default 3G/1G split
1465	  will also likely make your kernel incompatible with binary-only
1466	  kernel modules.
1467
1468	  If you are not absolutely sure what you are doing, leave this
1469	  option alone!
1470
1471	config VMSPLIT_3G
1472		bool "3G/1G user/kernel split"
1473	config VMSPLIT_3G_OPT
1474		depends on !X86_PAE
1475		bool "3G/1G user/kernel split (for full 1G low memory)"
1476	config VMSPLIT_2G
1477		bool "2G/2G user/kernel split"
1478	config VMSPLIT_2G_OPT
1479		depends on !X86_PAE
1480		bool "2G/2G user/kernel split (for full 2G low memory)"
1481	config VMSPLIT_1G
1482		bool "1G/3G user/kernel split"
1483endchoice
1484
1485config PAGE_OFFSET
1486	hex
1487	default 0xB0000000 if VMSPLIT_3G_OPT
1488	default 0x80000000 if VMSPLIT_2G
1489	default 0x78000000 if VMSPLIT_2G_OPT
1490	default 0x40000000 if VMSPLIT_1G
1491	default 0xC0000000
1492	depends on X86_32
1493
1494config HIGHMEM
1495	def_bool y
1496	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1497
1498config X86_PAE
1499	bool "PAE (Physical Address Extension) Support"
1500	depends on X86_32 && X86_HAVE_PAE
1501	select PHYS_ADDR_T_64BIT
1502	select SWIOTLB
1503	help
1504	  PAE is required for NX support, and furthermore enables
1505	  larger swapspace support for non-overcommit purposes. It
1506	  has the cost of more pagetable lookup overhead, and also
1507	  consumes more pagetable space per process.
1508
1509config X86_5LEVEL
1510	bool "Enable 5-level page tables support"
1511	default y
1512	select DYNAMIC_MEMORY_LAYOUT
1513	select SPARSEMEM_VMEMMAP
1514	depends on X86_64
1515	help
1516	  5-level paging enables access to larger address space:
1517	  up to 128 PiB of virtual address space and 4 PiB of
1518	  physical address space.
1519
1520	  It will be supported by future Intel CPUs.
1521
1522	  A kernel with the option enabled can be booted on machines that
1523	  support 4- or 5-level paging.
1524
1525	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1526	  information.
1527
1528	  Say N if unsure.
1529
1530config X86_DIRECT_GBPAGES
1531	def_bool y
1532	depends on X86_64
1533	help
1534	  Certain kernel features effectively disable kernel
1535	  linear 1 GB mappings (even if the CPU otherwise
1536	  supports them), so don't confuse the user by printing
1537	  that we have them enabled.
1538
1539config X86_CPA_STATISTICS
1540	bool "Enable statistic for Change Page Attribute"
1541	depends on DEBUG_FS
1542	help
1543	  Expose statistics about the Change Page Attribute mechanism, which
1544	  helps to determine the effectiveness of preserving large and huge
1545	  page mappings when mapping protections are changed.
1546
1547config X86_MEM_ENCRYPT
1548	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1549	select DYNAMIC_PHYSICAL_MASK
1550	def_bool n
1551
1552config AMD_MEM_ENCRYPT
1553	bool "AMD Secure Memory Encryption (SME) support"
1554	depends on X86_64 && CPU_SUP_AMD
1555	depends on EFI_STUB
1556	select DMA_COHERENT_POOL
1557	select ARCH_USE_MEMREMAP_PROT
1558	select INSTRUCTION_DECODER
1559	select ARCH_HAS_CC_PLATFORM
1560	select X86_MEM_ENCRYPT
1561	select UNACCEPTED_MEMORY
1562	help
1563	  Say yes to enable support for the encryption of system memory.
1564	  This requires an AMD processor that supports Secure Memory
1565	  Encryption (SME).
1566
1567# Common NUMA Features
1568config NUMA
1569	bool "NUMA Memory Allocation and Scheduler Support"
1570	depends on SMP
1571	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1572	default y if X86_BIGSMP
1573	select USE_PERCPU_NUMA_NODE_ID
1574	select OF_NUMA if OF
1575	help
1576	  Enable NUMA (Non-Uniform Memory Access) support.
1577
1578	  The kernel will try to allocate memory used by a CPU on the
1579	  local memory controller of the CPU and add some more
1580	  NUMA awareness to the kernel.
1581
1582	  For 64-bit this is recommended if the system is Intel Core i7
1583	  (or later), AMD Opteron, or EM64T NUMA.
1584
1585	  For 32-bit this is only needed if you boot a 32-bit
1586	  kernel on a 64-bit NUMA platform.
1587
1588	  Otherwise, you should say N.
1589
1590config AMD_NUMA
1591	def_bool y
1592	prompt "Old style AMD Opteron NUMA detection"
1593	depends on X86_64 && NUMA && PCI
1594	help
1595	  Enable AMD NUMA node topology detection.  You should say Y here if
1596	  you have a multi processor AMD system. This uses an old method to
1597	  read the NUMA configuration directly from the builtin Northbridge
1598	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1599	  which also takes priority if both are compiled in.
1600
1601config X86_64_ACPI_NUMA
1602	def_bool y
1603	prompt "ACPI NUMA detection"
1604	depends on X86_64 && NUMA && ACPI && PCI
1605	select ACPI_NUMA
1606	help
1607	  Enable ACPI SRAT based node topology detection.
1608
1609config NODES_SHIFT
1610	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1611	range 1 10
1612	default "10" if MAXSMP
1613	default "6" if X86_64
1614	default "3"
1615	depends on NUMA
1616	help
1617	  Specify the maximum number of NUMA Nodes available on the target
1618	  system.  Increases memory reserved to accommodate various tables.
1619
1620config ARCH_FLATMEM_ENABLE
1621	def_bool y
1622	depends on X86_32 && !NUMA
1623
1624config ARCH_SPARSEMEM_ENABLE
1625	def_bool y
1626	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1627	select SPARSEMEM_STATIC if X86_32
1628	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1629
1630config ARCH_SPARSEMEM_DEFAULT
1631	def_bool X86_64 || (NUMA && X86_32)
1632
1633config ARCH_SELECT_MEMORY_MODEL
1634	def_bool y
1635	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1636
1637config ARCH_MEMORY_PROBE
1638	bool "Enable sysfs memory/probe interface"
1639	depends on MEMORY_HOTPLUG
1640	help
1641	  This option enables a sysfs memory/probe interface for testing.
1642	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1643	  If you are unsure how to answer this question, answer N.
1644
1645config ARCH_PROC_KCORE_TEXT
1646	def_bool y
1647	depends on X86_64 && PROC_KCORE
1648
1649config ILLEGAL_POINTER_VALUE
1650	hex
1651	default 0 if X86_32
1652	default 0xdead000000000000 if X86_64
1653
1654config X86_PMEM_LEGACY_DEVICE
1655	bool
1656
1657config X86_PMEM_LEGACY
1658	tristate "Support non-standard NVDIMMs and ADR protected memory"
1659	depends on PHYS_ADDR_T_64BIT
1660	depends on BLK_DEV
1661	select X86_PMEM_LEGACY_DEVICE
1662	select NUMA_KEEP_MEMINFO if NUMA
1663	select LIBNVDIMM
1664	help
1665	  Treat memory marked using the non-standard e820 type of 12 as used
1666	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1667	  The kernel will offer these regions to the 'pmem' driver so
1668	  they can be used for persistent storage.
1669
1670	  Say Y if unsure.
1671
1672config HIGHPTE
1673	bool "Allocate 3rd-level pagetables from highmem"
1674	depends on HIGHMEM
1675	help
1676	  The VM uses one page table entry for each page of physical memory.
1677	  For systems with a lot of RAM, this can be wasteful of precious
1678	  low memory.  Setting this option will put user-space page table
1679	  entries in high memory.
1680
1681config X86_CHECK_BIOS_CORRUPTION
1682	bool "Check for low memory corruption"
1683	help
1684	  Periodically check for memory corruption in low memory, which
1685	  is suspected to be caused by BIOS.  Even when enabled in the
1686	  configuration, it is disabled at runtime.  Enable it by
1687	  setting "memory_corruption_check=1" on the kernel command
1688	  line.  By default it scans the low 64k of memory every 60
1689	  seconds; see the memory_corruption_check_size and
1690	  memory_corruption_check_period parameters in
1691	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1692
1693	  When enabled with the default parameters, this option has
1694	  almost no overhead, as it reserves a relatively small amount
1695	  of memory and scans it infrequently.  It both detects corruption
1696	  and prevents it from affecting the running system.
1697
1698	  It is, however, intended as a diagnostic tool; if repeatable
1699	  BIOS-originated corruption always affects the same memory,
1700	  you can use memmap= to prevent the kernel from using that
1701	  memory.
1702
1703config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1704	bool "Set the default setting of memory_corruption_check"
1705	depends on X86_CHECK_BIOS_CORRUPTION
1706	default y
1707	help
1708	  Set whether the default state of memory_corruption_check is
1709	  on or off.
1710
1711config MATH_EMULATION
1712	bool
1713	depends on MODIFY_LDT_SYSCALL
1714	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1715	help
1716	  Linux can emulate a math coprocessor (used for floating point
1717	  operations) if you don't have one. 486DX and Pentium processors have
1718	  a math coprocessor built in, 486SX and 386 do not, unless you added
1719	  a 487DX or 387, respectively. (The messages during boot time can
1720	  give you some hints here ["man dmesg"].) Everyone needs either a
1721	  coprocessor or this emulation.
1722
1723	  If you don't have a math coprocessor, you need to say Y here; if you
1724	  say Y here even though you have a coprocessor, the coprocessor will
1725	  be used nevertheless. (This behavior can be changed with the kernel
1726	  command line option "no387", which comes handy if your coprocessor
1727	  is broken. Try "man bootparam" or see the documentation of your boot
1728	  loader (lilo or loadlin) about how to pass options to the kernel at
1729	  boot time.) This means that it is a good idea to say Y here if you
1730	  intend to use this kernel on different machines.
1731
1732	  More information about the internals of the Linux math coprocessor
1733	  emulation can be found in <file:arch/x86/math-emu/README>.
1734
1735	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1736	  kernel, it won't hurt.
1737
1738config MTRR
1739	def_bool y
1740	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1741	help
1742	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1743	  the Memory Type Range Registers (MTRRs) may be used to control
1744	  processor access to memory ranges. This is most useful if you have
1745	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1746	  allows bus write transfers to be combined into a larger transfer
1747	  before bursting over the PCI/AGP bus. This can increase performance
1748	  of image write operations 2.5 times or more. Saying Y here creates a
1749	  /proc/mtrr file which may be used to manipulate your processor's
1750	  MTRRs. Typically the X server should use this.
1751
1752	  This code has a reasonably generic interface so that similar
1753	  control registers on other processors can be easily supported
1754	  as well:
1755
1756	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1757	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1758	  these, the ARRs are used to emulate the MTRRs.
1759	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1760	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1761	  write-combining. All of these processors are supported by this code
1762	  and it makes sense to say Y here if you have one of them.
1763
1764	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1765	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1766	  can lead to all sorts of problems, so it's good to say Y here.
1767
1768	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1769	  just add about 9 KB to your kernel.
1770
1771	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1772
1773config MTRR_SANITIZER
1774	def_bool y
1775	prompt "MTRR cleanup support"
1776	depends on MTRR
1777	help
1778	  Convert MTRR layout from continuous to discrete, so X drivers can
1779	  add writeback entries.
1780
1781	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1782	  The largest mtrr entry size for a continuous block can be set with
1783	  mtrr_chunk_size.
1784
1785	  If unsure, say Y.
1786
1787config MTRR_SANITIZER_ENABLE_DEFAULT
1788	int "MTRR cleanup enable value (0-1)"
1789	range 0 1
1790	default "0"
1791	depends on MTRR_SANITIZER
1792	help
1793	  Enable mtrr cleanup default value
1794
1795config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1796	int "MTRR cleanup spare reg num (0-7)"
1797	range 0 7
1798	default "1"
1799	depends on MTRR_SANITIZER
1800	help
1801	  mtrr cleanup spare entries default, it can be changed via
1802	  mtrr_spare_reg_nr=N on the kernel command line.
1803
1804config X86_PAT
1805	def_bool y
1806	prompt "x86 PAT support" if EXPERT
1807	depends on MTRR
1808	select ARCH_USES_PG_ARCH_2
1809	help
1810	  Use PAT attributes to setup page level cache control.
1811
1812	  PATs are the modern equivalents of MTRRs and are much more
1813	  flexible than MTRRs.
1814
1815	  Say N here if you see bootup problems (boot crash, boot hang,
1816	  spontaneous reboots) or a non-working video driver.
1817
1818	  If unsure, say Y.
1819
1820config X86_UMIP
1821	def_bool y
1822	prompt "User Mode Instruction Prevention" if EXPERT
1823	help
1824	  User Mode Instruction Prevention (UMIP) is a security feature in
1825	  some x86 processors. If enabled, a general protection fault is
1826	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1827	  executed in user mode. These instructions unnecessarily expose
1828	  information about the hardware state.
1829
1830	  The vast majority of applications do not use these instructions.
1831	  For the very few that do, software emulation is provided in
1832	  specific cases in protected and virtual-8086 modes. Emulated
1833	  results are dummy.
1834
1835config CC_HAS_IBT
1836	# GCC >= 9 and binutils >= 2.29
1837	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1838	# Clang/LLVM >= 14
1839	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1840	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1841	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1842		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1843		  $(as-instr,endbr64)
1844
1845config X86_CET
1846	def_bool n
1847	help
1848	  CET features configured (Shadow stack or IBT)
1849
1850config X86_KERNEL_IBT
1851	prompt "Indirect Branch Tracking"
1852	def_bool y
1853	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1854	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1855	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1856	select OBJTOOL
1857	select X86_CET
1858	help
1859	  Build the kernel with support for Indirect Branch Tracking, a
1860	  hardware support course-grain forward-edge Control Flow Integrity
1861	  protection. It enforces that all indirect calls must land on
1862	  an ENDBR instruction, as such, the compiler will instrument the
1863	  code with them to make this happen.
1864
1865	  In addition to building the kernel with IBT, seal all functions that
1866	  are not indirect call targets, avoiding them ever becoming one.
1867
1868	  This requires LTO like objtool runs and will slow down the build. It
1869	  does significantly reduce the number of ENDBR instructions in the
1870	  kernel image.
1871
1872config X86_INTEL_MEMORY_PROTECTION_KEYS
1873	prompt "Memory Protection Keys"
1874	def_bool y
1875	# Note: only available in 64-bit mode
1876	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1877	select ARCH_USES_HIGH_VMA_FLAGS
1878	select ARCH_HAS_PKEYS
1879	help
1880	  Memory Protection Keys provides a mechanism for enforcing
1881	  page-based protections, but without requiring modification of the
1882	  page tables when an application changes protection domains.
1883
1884	  For details, see Documentation/core-api/protection-keys.rst
1885
1886	  If unsure, say y.
1887
1888config ARCH_PKEY_BITS
1889	int
1890	default 4
1891
1892choice
1893	prompt "TSX enable mode"
1894	depends on CPU_SUP_INTEL
1895	default X86_INTEL_TSX_MODE_OFF
1896	help
1897	  Intel's TSX (Transactional Synchronization Extensions) feature
1898	  allows to optimize locking protocols through lock elision which
1899	  can lead to a noticeable performance boost.
1900
1901	  On the other hand it has been shown that TSX can be exploited
1902	  to form side channel attacks (e.g. TAA) and chances are there
1903	  will be more of those attacks discovered in the future.
1904
1905	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1906	  might override this decision by tsx=on the command line parameter.
1907	  Even with TSX enabled, the kernel will attempt to enable the best
1908	  possible TAA mitigation setting depending on the microcode available
1909	  for the particular machine.
1910
1911	  This option allows to set the default tsx mode between tsx=on, =off
1912	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1913	  details.
1914
1915	  Say off if not sure, auto if TSX is in use but it should be used on safe
1916	  platforms or on if TSX is in use and the security aspect of tsx is not
1917	  relevant.
1918
1919config X86_INTEL_TSX_MODE_OFF
1920	bool "off"
1921	help
1922	  TSX is disabled if possible - equals to tsx=off command line parameter.
1923
1924config X86_INTEL_TSX_MODE_ON
1925	bool "on"
1926	help
1927	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1928	  line parameter.
1929
1930config X86_INTEL_TSX_MODE_AUTO
1931	bool "auto"
1932	help
1933	  TSX is enabled on TSX capable HW that is believed to be safe against
1934	  side channel attacks- equals the tsx=auto command line parameter.
1935endchoice
1936
1937config X86_SGX
1938	bool "Software Guard eXtensions (SGX)"
1939	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1940	depends on CRYPTO=y
1941	depends on CRYPTO_SHA256=y
1942	select MMU_NOTIFIER
1943	select NUMA_KEEP_MEMINFO if NUMA
1944	select XARRAY_MULTI
1945	help
1946	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1947	  that can be used by applications to set aside private regions of code
1948	  and data, referred to as enclaves. An enclave's private memory can
1949	  only be accessed by code running within the enclave. Accesses from
1950	  outside the enclave, including other enclaves, are disallowed by
1951	  hardware.
1952
1953	  If unsure, say N.
1954
1955config X86_USER_SHADOW_STACK
1956	bool "X86 userspace shadow stack"
1957	depends on AS_WRUSS
1958	depends on X86_64
1959	select ARCH_USES_HIGH_VMA_FLAGS
1960	select ARCH_HAS_USER_SHADOW_STACK
1961	select X86_CET
1962	help
1963	  Shadow stack protection is a hardware feature that detects function
1964	  return address corruption.  This helps mitigate ROP attacks.
1965	  Applications must be enabled to use it, and old userspace does not
1966	  get protection "for free".
1967
1968	  CPUs supporting shadow stacks were first released in 2020.
1969
1970	  See Documentation/arch/x86/shstk.rst for more information.
1971
1972	  If unsure, say N.
1973
1974config INTEL_TDX_HOST
1975	bool "Intel Trust Domain Extensions (TDX) host support"
1976	depends on CPU_SUP_INTEL
1977	depends on X86_64
1978	depends on KVM_INTEL
1979	depends on X86_X2APIC
1980	select ARCH_KEEP_MEMBLOCK
1981	depends on CONTIG_ALLOC
1982	depends on !KEXEC_CORE
1983	depends on X86_MCE
1984	help
1985	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1986	  host and certain physical attacks.  This option enables necessary TDX
1987	  support in the host kernel to run confidential VMs.
1988
1989	  If unsure, say N.
1990
1991config EFI
1992	bool "EFI runtime service support"
1993	depends on ACPI
1994	select UCS2_STRING
1995	select EFI_RUNTIME_WRAPPERS
1996	select ARCH_USE_MEMREMAP_PROT
1997	select EFI_RUNTIME_MAP if KEXEC_CORE
1998	help
1999	  This enables the kernel to use EFI runtime services that are
2000	  available (such as the EFI variable services).
2001
2002	  This option is only useful on systems that have EFI firmware.
2003	  In addition, you should use the latest ELILO loader available
2004	  at <http://elilo.sourceforge.net> in order to take advantage
2005	  of EFI runtime services. However, even with this option, the
2006	  resultant kernel should continue to boot on existing non-EFI
2007	  platforms.
2008
2009config EFI_STUB
2010	bool "EFI stub support"
2011	depends on EFI
2012	select RELOCATABLE
2013	help
2014	  This kernel feature allows a bzImage to be loaded directly
2015	  by EFI firmware without the use of a bootloader.
2016
2017	  See Documentation/admin-guide/efi-stub.rst for more information.
2018
2019config EFI_HANDOVER_PROTOCOL
2020	bool "EFI handover protocol (DEPRECATED)"
2021	depends on EFI_STUB
2022	default y
2023	help
2024	  Select this in order to include support for the deprecated EFI
2025	  handover protocol, which defines alternative entry points into the
2026	  EFI stub.  This is a practice that has no basis in the UEFI
2027	  specification, and requires a priori knowledge on the part of the
2028	  bootloader about Linux/x86 specific ways of passing the command line
2029	  and initrd, and where in memory those assets may be loaded.
2030
2031	  If in doubt, say Y. Even though the corresponding support is not
2032	  present in upstream GRUB or other bootloaders, most distros build
2033	  GRUB with numerous downstream patches applied, and may rely on the
2034	  handover protocol as as result.
2035
2036config EFI_MIXED
2037	bool "EFI mixed-mode support"
2038	depends on EFI_STUB && X86_64
2039	help
2040	  Enabling this feature allows a 64-bit kernel to be booted
2041	  on a 32-bit firmware, provided that your CPU supports 64-bit
2042	  mode.
2043
2044	  Note that it is not possible to boot a mixed-mode enabled
2045	  kernel via the EFI boot stub - a bootloader that supports
2046	  the EFI handover protocol must be used.
2047
2048	  If unsure, say N.
2049
2050config EFI_RUNTIME_MAP
2051	bool "Export EFI runtime maps to sysfs" if EXPERT
2052	depends on EFI
2053	help
2054	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2055	  That memory map is required by the 2nd kernel to set up EFI virtual
2056	  mappings after kexec, but can also be used for debugging purposes.
2057
2058	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2059
2060source "kernel/Kconfig.hz"
2061
2062config ARCH_SUPPORTS_KEXEC
2063	def_bool y
2064
2065config ARCH_SUPPORTS_KEXEC_FILE
2066	def_bool X86_64
2067
2068config ARCH_SELECTS_KEXEC_FILE
2069	def_bool y
2070	depends on KEXEC_FILE
2071	select HAVE_IMA_KEXEC if IMA
2072
2073config ARCH_SUPPORTS_KEXEC_PURGATORY
2074	def_bool y
2075
2076config ARCH_SUPPORTS_KEXEC_SIG
2077	def_bool y
2078
2079config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2080	def_bool y
2081
2082config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2083	def_bool y
2084
2085config ARCH_SUPPORTS_KEXEC_JUMP
2086	def_bool y
2087
2088config ARCH_SUPPORTS_CRASH_DUMP
2089	def_bool X86_64 || (X86_32 && HIGHMEM)
2090
2091config ARCH_DEFAULT_CRASH_DUMP
2092	def_bool y
2093
2094config ARCH_SUPPORTS_CRASH_HOTPLUG
2095	def_bool y
2096
2097config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2098	def_bool CRASH_RESERVE
2099
2100config PHYSICAL_START
2101	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2102	default "0x1000000"
2103	help
2104	  This gives the physical address where the kernel is loaded.
2105
2106	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2107	  will decompress itself to above physical address and run from there.
2108	  Otherwise, bzImage will run from the address where it has been loaded
2109	  by the boot loader. The only exception is if it is loaded below the
2110	  above physical address, in which case it will relocate itself there.
2111
2112	  In normal kdump cases one does not have to set/change this option
2113	  as now bzImage can be compiled as a completely relocatable image
2114	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2115	  address. This option is mainly useful for the folks who don't want
2116	  to use a bzImage for capturing the crash dump and want to use a
2117	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2118	  to be specifically compiled to run from a specific memory area
2119	  (normally a reserved region) and this option comes handy.
2120
2121	  So if you are using bzImage for capturing the crash dump,
2122	  leave the value here unchanged to 0x1000000 and set
2123	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2124	  for capturing the crash dump change this value to start of
2125	  the reserved region.  In other words, it can be set based on
2126	  the "X" value as specified in the "crashkernel=YM@XM"
2127	  command line boot parameter passed to the panic-ed
2128	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2129	  for more details about crash dumps.
2130
2131	  Usage of bzImage for capturing the crash dump is recommended as
2132	  one does not have to build two kernels. Same kernel can be used
2133	  as production kernel and capture kernel. Above option should have
2134	  gone away after relocatable bzImage support is introduced. But it
2135	  is present because there are users out there who continue to use
2136	  vmlinux for dump capture. This option should go away down the
2137	  line.
2138
2139	  Don't change this unless you know what you are doing.
2140
2141config RELOCATABLE
2142	bool "Build a relocatable kernel"
2143	default y
2144	help
2145	  This builds a kernel image that retains relocation information
2146	  so it can be loaded someplace besides the default 1MB.
2147	  The relocations tend to make the kernel binary about 10% larger,
2148	  but are discarded at runtime.
2149
2150	  One use is for the kexec on panic case where the recovery kernel
2151	  must live at a different physical address than the primary
2152	  kernel.
2153
2154	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2155	  it has been loaded at and the compile time physical address
2156	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2157
2158config RANDOMIZE_BASE
2159	bool "Randomize the address of the kernel image (KASLR)"
2160	depends on RELOCATABLE
2161	default y
2162	help
2163	  In support of Kernel Address Space Layout Randomization (KASLR),
2164	  this randomizes the physical address at which the kernel image
2165	  is decompressed and the virtual address where the kernel
2166	  image is mapped, as a security feature that deters exploit
2167	  attempts relying on knowledge of the location of kernel
2168	  code internals.
2169
2170	  On 64-bit, the kernel physical and virtual addresses are
2171	  randomized separately. The physical address will be anywhere
2172	  between 16MB and the top of physical memory (up to 64TB). The
2173	  virtual address will be randomized from 16MB up to 1GB (9 bits
2174	  of entropy). Note that this also reduces the memory space
2175	  available to kernel modules from 1.5GB to 1GB.
2176
2177	  On 32-bit, the kernel physical and virtual addresses are
2178	  randomized together. They will be randomized from 16MB up to
2179	  512MB (8 bits of entropy).
2180
2181	  Entropy is generated using the RDRAND instruction if it is
2182	  supported. If RDTSC is supported, its value is mixed into
2183	  the entropy pool as well. If neither RDRAND nor RDTSC are
2184	  supported, then entropy is read from the i8254 timer. The
2185	  usable entropy is limited by the kernel being built using
2186	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2187	  minimum of 2MB. As a result, only 10 bits of entropy are
2188	  theoretically possible, but the implementations are further
2189	  limited due to memory layouts.
2190
2191	  If unsure, say Y.
2192
2193# Relocation on x86 needs some additional build support
2194config X86_NEED_RELOCS
2195	def_bool y
2196	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2197
2198config PHYSICAL_ALIGN
2199	hex "Alignment value to which kernel should be aligned"
2200	default "0x200000"
2201	range 0x2000 0x1000000 if X86_32
2202	range 0x200000 0x1000000 if X86_64
2203	help
2204	  This value puts the alignment restrictions on physical address
2205	  where kernel is loaded and run from. Kernel is compiled for an
2206	  address which meets above alignment restriction.
2207
2208	  If bootloader loads the kernel at a non-aligned address and
2209	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2210	  address aligned to above value and run from there.
2211
2212	  If bootloader loads the kernel at a non-aligned address and
2213	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2214	  load address and decompress itself to the address it has been
2215	  compiled for and run from there. The address for which kernel is
2216	  compiled already meets above alignment restrictions. Hence the
2217	  end result is that kernel runs from a physical address meeting
2218	  above alignment restrictions.
2219
2220	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2221	  this value must be a multiple of 0x200000.
2222
2223	  Don't change this unless you know what you are doing.
2224
2225config DYNAMIC_MEMORY_LAYOUT
2226	bool
2227	help
2228	  This option makes base addresses of vmalloc and vmemmap as well as
2229	  __PAGE_OFFSET movable during boot.
2230
2231config RANDOMIZE_MEMORY
2232	bool "Randomize the kernel memory sections"
2233	depends on X86_64
2234	depends on RANDOMIZE_BASE
2235	select DYNAMIC_MEMORY_LAYOUT
2236	default RANDOMIZE_BASE
2237	help
2238	  Randomizes the base virtual address of kernel memory sections
2239	  (physical memory mapping, vmalloc & vmemmap). This security feature
2240	  makes exploits relying on predictable memory locations less reliable.
2241
2242	  The order of allocations remains unchanged. Entropy is generated in
2243	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2244	  configuration have in average 30,000 different possible virtual
2245	  addresses for each memory section.
2246
2247	  If unsure, say Y.
2248
2249config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2250	hex "Physical memory mapping padding" if EXPERT
2251	depends on RANDOMIZE_MEMORY
2252	default "0xa" if MEMORY_HOTPLUG
2253	default "0x0"
2254	range 0x1 0x40 if MEMORY_HOTPLUG
2255	range 0x0 0x40
2256	help
2257	  Define the padding in terabytes added to the existing physical
2258	  memory size during kernel memory randomization. It is useful
2259	  for memory hotplug support but reduces the entropy available for
2260	  address randomization.
2261
2262	  If unsure, leave at the default value.
2263
2264config ADDRESS_MASKING
2265	bool "Linear Address Masking support"
2266	depends on X86_64
2267	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2268	help
2269	  Linear Address Masking (LAM) modifies the checking that is applied
2270	  to 64-bit linear addresses, allowing software to use of the
2271	  untranslated address bits for metadata.
2272
2273	  The capability can be used for efficient address sanitizers (ASAN)
2274	  implementation and for optimizations in JITs.
2275
2276config HOTPLUG_CPU
2277	def_bool y
2278	depends on SMP
2279
2280config COMPAT_VDSO
2281	def_bool n
2282	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2283	depends on COMPAT_32
2284	help
2285	  Certain buggy versions of glibc will crash if they are
2286	  presented with a 32-bit vDSO that is not mapped at the address
2287	  indicated in its segment table.
2288
2289	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2290	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2291	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2292	  the only released version with the bug, but OpenSUSE 9
2293	  contains a buggy "glibc 2.3.2".
2294
2295	  The symptom of the bug is that everything crashes on startup, saying:
2296	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2297
2298	  Saying Y here changes the default value of the vdso32 boot
2299	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2300	  This works around the glibc bug but hurts performance.
2301
2302	  If unsure, say N: if you are compiling your own kernel, you
2303	  are unlikely to be using a buggy version of glibc.
2304
2305choice
2306	prompt "vsyscall table for legacy applications"
2307	depends on X86_64
2308	default LEGACY_VSYSCALL_XONLY
2309	help
2310	  Legacy user code that does not know how to find the vDSO expects
2311	  to be able to issue three syscalls by calling fixed addresses in
2312	  kernel space. Since this location is not randomized with ASLR,
2313	  it can be used to assist security vulnerability exploitation.
2314
2315	  This setting can be changed at boot time via the kernel command
2316	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2317	  is deprecated and can only be enabled using the kernel command
2318	  line.
2319
2320	  On a system with recent enough glibc (2.14 or newer) and no
2321	  static binaries, you can say None without a performance penalty
2322	  to improve security.
2323
2324	  If unsure, select "Emulate execution only".
2325
2326	config LEGACY_VSYSCALL_XONLY
2327		bool "Emulate execution only"
2328		help
2329		  The kernel traps and emulates calls into the fixed vsyscall
2330		  address mapping and does not allow reads.  This
2331		  configuration is recommended when userspace might use the
2332		  legacy vsyscall area but support for legacy binary
2333		  instrumentation of legacy code is not needed.  It mitigates
2334		  certain uses of the vsyscall area as an ASLR-bypassing
2335		  buffer.
2336
2337	config LEGACY_VSYSCALL_NONE
2338		bool "None"
2339		help
2340		  There will be no vsyscall mapping at all. This will
2341		  eliminate any risk of ASLR bypass due to the vsyscall
2342		  fixed address mapping. Attempts to use the vsyscalls
2343		  will be reported to dmesg, so that either old or
2344		  malicious userspace programs can be identified.
2345
2346endchoice
2347
2348config CMDLINE_BOOL
2349	bool "Built-in kernel command line"
2350	help
2351	  Allow for specifying boot arguments to the kernel at
2352	  build time.  On some systems (e.g. embedded ones), it is
2353	  necessary or convenient to provide some or all of the
2354	  kernel boot arguments with the kernel itself (that is,
2355	  to not rely on the boot loader to provide them.)
2356
2357	  To compile command line arguments into the kernel,
2358	  set this option to 'Y', then fill in the
2359	  boot arguments in CONFIG_CMDLINE.
2360
2361	  Systems with fully functional boot loaders (i.e. non-embedded)
2362	  should leave this option set to 'N'.
2363
2364config CMDLINE
2365	string "Built-in kernel command string"
2366	depends on CMDLINE_BOOL
2367	default ""
2368	help
2369	  Enter arguments here that should be compiled into the kernel
2370	  image and used at boot time.  If the boot loader provides a
2371	  command line at boot time, it is appended to this string to
2372	  form the full kernel command line, when the system boots.
2373
2374	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2375	  change this behavior.
2376
2377	  In most cases, the command line (whether built-in or provided
2378	  by the boot loader) should specify the device for the root
2379	  file system.
2380
2381config CMDLINE_OVERRIDE
2382	bool "Built-in command line overrides boot loader arguments"
2383	depends on CMDLINE_BOOL && CMDLINE != ""
2384	help
2385	  Set this option to 'Y' to have the kernel ignore the boot loader
2386	  command line, and use ONLY the built-in command line.
2387
2388	  This is used to work around broken boot loaders.  This should
2389	  be set to 'N' under normal conditions.
2390
2391config MODIFY_LDT_SYSCALL
2392	bool "Enable the LDT (local descriptor table)" if EXPERT
2393	default y
2394	help
2395	  Linux can allow user programs to install a per-process x86
2396	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2397	  call.  This is required to run 16-bit or segmented code such as
2398	  DOSEMU or some Wine programs.  It is also used by some very old
2399	  threading libraries.
2400
2401	  Enabling this feature adds a small amount of overhead to
2402	  context switches and increases the low-level kernel attack
2403	  surface.  Disabling it removes the modify_ldt(2) system call.
2404
2405	  Saying 'N' here may make sense for embedded or server kernels.
2406
2407config STRICT_SIGALTSTACK_SIZE
2408	bool "Enforce strict size checking for sigaltstack"
2409	depends on DYNAMIC_SIGFRAME
2410	help
2411	  For historical reasons MINSIGSTKSZ is a constant which became
2412	  already too small with AVX512 support. Add a mechanism to
2413	  enforce strict checking of the sigaltstack size against the
2414	  real size of the FPU frame. This option enables the check
2415	  by default. It can also be controlled via the kernel command
2416	  line option 'strict_sas_size' independent of this config
2417	  switch. Enabling it might break existing applications which
2418	  allocate a too small sigaltstack but 'work' because they
2419	  never get a signal delivered.
2420
2421	  Say 'N' unless you want to really enforce this check.
2422
2423config CFI_AUTO_DEFAULT
2424	bool "Attempt to use FineIBT by default at boot time"
2425	depends on FINEIBT
2426	default y
2427	help
2428	  Attempt to use FineIBT by default at boot time. If enabled,
2429	  this is the same as booting with "cfi=auto". If disabled,
2430	  this is the same as booting with "cfi=kcfi".
2431
2432source "kernel/livepatch/Kconfig"
2433
2434config X86_BUS_LOCK_DETECT
2435	bool "Split Lock Detect and Bus Lock Detect support"
2436	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2437	default y
2438	help
2439	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2440	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2441
2442endmenu
2443
2444config CC_HAS_NAMED_AS
2445	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2446	depends on CC_IS_GCC
2447
2448config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2449	def_bool CC_IS_GCC && GCC_VERSION >= 130300
2450
2451config USE_X86_SEG_SUPPORT
2452	def_bool y
2453	depends on CC_HAS_NAMED_AS
2454	#
2455	# -fsanitize=kernel-address (KASAN) and -fsanitize=thread
2456	# (KCSAN) are incompatible with named address spaces with
2457	# GCC < 13.3 - see GCC PR sanitizer/111736.
2458	#
2459	depends on !(KASAN || KCSAN) || CC_HAS_NAMED_AS_FIXED_SANITIZERS
2460
2461config CC_HAS_SLS
2462	def_bool $(cc-option,-mharden-sls=all)
2463
2464config CC_HAS_RETURN_THUNK
2465	def_bool $(cc-option,-mfunction-return=thunk-extern)
2466
2467config CC_HAS_ENTRY_PADDING
2468	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2469
2470config FUNCTION_PADDING_CFI
2471	int
2472	default 59 if FUNCTION_ALIGNMENT_64B
2473	default 27 if FUNCTION_ALIGNMENT_32B
2474	default 11 if FUNCTION_ALIGNMENT_16B
2475	default  3 if FUNCTION_ALIGNMENT_8B
2476	default  0
2477
2478# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2479# except Kconfig can't do arithmetic :/
2480config FUNCTION_PADDING_BYTES
2481	int
2482	default FUNCTION_PADDING_CFI if CFI_CLANG
2483	default FUNCTION_ALIGNMENT
2484
2485config CALL_PADDING
2486	def_bool n
2487	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2488	select FUNCTION_ALIGNMENT_16B
2489
2490config FINEIBT
2491	def_bool y
2492	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2493	select CALL_PADDING
2494
2495config HAVE_CALL_THUNKS
2496	def_bool y
2497	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2498
2499config CALL_THUNKS
2500	def_bool n
2501	select CALL_PADDING
2502
2503config PREFIX_SYMBOLS
2504	def_bool y
2505	depends on CALL_PADDING && !CFI_CLANG
2506
2507menuconfig CPU_MITIGATIONS
2508	bool "Mitigations for CPU vulnerabilities"
2509	default y
2510	help
2511	  Say Y here to enable options which enable mitigations for hardware
2512	  vulnerabilities (usually related to speculative execution).
2513	  Mitigations can be disabled or restricted to SMT systems at runtime
2514	  via the "mitigations" kernel parameter.
2515
2516	  If you say N, all mitigations will be disabled.  This CANNOT be
2517	  overridden at runtime.
2518
2519	  Say 'Y', unless you really know what you are doing.
2520
2521if CPU_MITIGATIONS
2522
2523config MITIGATION_PAGE_TABLE_ISOLATION
2524	bool "Remove the kernel mapping in user mode"
2525	default y
2526	depends on (X86_64 || X86_PAE)
2527	help
2528	  This feature reduces the number of hardware side channels by
2529	  ensuring that the majority of kernel addresses are not mapped
2530	  into userspace.
2531
2532	  See Documentation/arch/x86/pti.rst for more details.
2533
2534config MITIGATION_RETPOLINE
2535	bool "Avoid speculative indirect branches in kernel"
2536	select OBJTOOL if HAVE_OBJTOOL
2537	default y
2538	help
2539	  Compile kernel with the retpoline compiler options to guard against
2540	  kernel-to-user data leaks by avoiding speculative indirect
2541	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2542	  support for full protection. The kernel may run slower.
2543
2544config MITIGATION_RETHUNK
2545	bool "Enable return-thunks"
2546	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2547	select OBJTOOL if HAVE_OBJTOOL
2548	default y if X86_64
2549	help
2550	  Compile the kernel with the return-thunks compiler option to guard
2551	  against kernel-to-user data leaks by avoiding return speculation.
2552	  Requires a compiler with -mfunction-return=thunk-extern
2553	  support for full protection. The kernel may run slower.
2554
2555config MITIGATION_UNRET_ENTRY
2556	bool "Enable UNRET on kernel entry"
2557	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2558	default y
2559	help
2560	  Compile the kernel with support for the retbleed=unret mitigation.
2561
2562config MITIGATION_CALL_DEPTH_TRACKING
2563	bool "Mitigate RSB underflow with call depth tracking"
2564	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2565	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2566	select CALL_THUNKS
2567	default y
2568	help
2569	  Compile the kernel with call depth tracking to mitigate the Intel
2570	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2571	  by default and needs to be enabled on the kernel command line via the
2572	  retbleed=stuff option. For non-affected systems the overhead of this
2573	  option is marginal as the call depth tracking is using run-time
2574	  generated call thunks in a compiler generated padding area and call
2575	  patching. This increases text size by ~5%. For non affected systems
2576	  this space is unused. On affected SKL systems this results in a
2577	  significant performance gain over the IBRS mitigation.
2578
2579config CALL_THUNKS_DEBUG
2580	bool "Enable call thunks and call depth tracking debugging"
2581	depends on MITIGATION_CALL_DEPTH_TRACKING
2582	select FUNCTION_ALIGNMENT_32B
2583	default n
2584	help
2585	  Enable call/ret counters for imbalance detection and build in
2586	  a noisy dmesg about callthunks generation and call patching for
2587	  trouble shooting. The debug prints need to be enabled on the
2588	  kernel command line with 'debug-callthunks'.
2589	  Only enable this when you are debugging call thunks as this
2590	  creates a noticeable runtime overhead. If unsure say N.
2591
2592config MITIGATION_IBPB_ENTRY
2593	bool "Enable IBPB on kernel entry"
2594	depends on CPU_SUP_AMD && X86_64
2595	default y
2596	help
2597	  Compile the kernel with support for the retbleed=ibpb mitigation.
2598
2599config MITIGATION_IBRS_ENTRY
2600	bool "Enable IBRS on kernel entry"
2601	depends on CPU_SUP_INTEL && X86_64
2602	default y
2603	help
2604	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2605	  This mitigates both spectre_v2 and retbleed at great cost to
2606	  performance.
2607
2608config MITIGATION_SRSO
2609	bool "Mitigate speculative RAS overflow on AMD"
2610	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2611	default y
2612	help
2613	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2614
2615config MITIGATION_SLS
2616	bool "Mitigate Straight-Line-Speculation"
2617	depends on CC_HAS_SLS && X86_64
2618	select OBJTOOL if HAVE_OBJTOOL
2619	default n
2620	help
2621	  Compile the kernel with straight-line-speculation options to guard
2622	  against straight line speculation. The kernel image might be slightly
2623	  larger.
2624
2625config MITIGATION_GDS
2626	bool "Mitigate Gather Data Sampling"
2627	depends on CPU_SUP_INTEL
2628	default y
2629	help
2630	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2631	  vulnerability which allows unprivileged speculative access to data
2632	  which was previously stored in vector registers. The attacker uses gather
2633	  instructions to infer the stale vector register data.
2634
2635config MITIGATION_RFDS
2636	bool "RFDS Mitigation"
2637	depends on CPU_SUP_INTEL
2638	default y
2639	help
2640	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2641	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2642	  allows unprivileged speculative access to stale data previously
2643	  stored in floating point, vector and integer registers.
2644	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2645
2646config MITIGATION_SPECTRE_BHI
2647	bool "Mitigate Spectre-BHB (Branch History Injection)"
2648	depends on CPU_SUP_INTEL
2649	default y
2650	help
2651	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2652	  where the branch history buffer is poisoned to speculatively steer
2653	  indirect branches.
2654	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2655
2656config MITIGATION_MDS
2657	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2658	depends on CPU_SUP_INTEL
2659	default y
2660	help
2661	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2662	  a hardware vulnerability which allows unprivileged speculative access
2663	  to data which is available in various CPU internal buffers.
2664	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2665
2666config MITIGATION_TAA
2667	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2668	depends on CPU_SUP_INTEL
2669	default y
2670	help
2671	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2672	  vulnerability that allows unprivileged speculative access to data
2673	  which is available in various CPU internal buffers by using
2674	  asynchronous aborts within an Intel TSX transactional region.
2675	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2676
2677config MITIGATION_MMIO_STALE_DATA
2678	bool "Mitigate MMIO Stale Data hardware bug"
2679	depends on CPU_SUP_INTEL
2680	default y
2681	help
2682	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2683	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2684	  vulnerabilities that can expose data. The vulnerabilities require the
2685	  attacker to have access to MMIO.
2686	  See also
2687	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2688
2689config MITIGATION_L1TF
2690	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2691	depends on CPU_SUP_INTEL
2692	default y
2693	help
2694	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2695	  hardware vulnerability which allows unprivileged speculative access to data
2696	  available in the Level 1 Data Cache.
2697	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2698
2699config MITIGATION_RETBLEED
2700	bool "Mitigate RETBleed hardware bug"
2701	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2702	default y
2703	help
2704	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2705	  with Return Instructions) vulnerability.  RETBleed is a speculative
2706	  execution attack which takes advantage of microarchitectural behavior
2707	  in many modern microprocessors, similar to Spectre v2. An
2708	  unprivileged attacker can use these flaws to bypass conventional
2709	  memory security restrictions to gain read access to privileged memory
2710	  that would otherwise be inaccessible.
2711
2712config MITIGATION_SPECTRE_V1
2713	bool "Mitigate SPECTRE V1 hardware bug"
2714	default y
2715	help
2716	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2717	  class of side channel attacks that takes advantage of speculative
2718	  execution that bypasses conditional branch instructions used for
2719	  memory access bounds check.
2720	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2721
2722config MITIGATION_SPECTRE_V2
2723	bool "Mitigate SPECTRE V2 hardware bug"
2724	default y
2725	help
2726	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2727	  V2 is a class of side channel attacks that takes advantage of
2728	  indirect branch predictors inside the processor. In Spectre variant 2
2729	  attacks, the attacker can steer speculative indirect branches in the
2730	  victim to gadget code by poisoning the branch target buffer of a CPU
2731	  used for predicting indirect branch addresses.
2732	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2733
2734config MITIGATION_SRBDS
2735	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2736	depends on CPU_SUP_INTEL
2737	default y
2738	help
2739	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2740	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2741	  Sampling (MDS) techniques to infer values returned from special
2742	  register accesses. An unprivileged user can extract values returned
2743	  from RDRAND and RDSEED executed on another core or sibling thread
2744	  using MDS techniques.
2745	  See also
2746	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2747
2748config MITIGATION_SSB
2749	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2750	default y
2751	help
2752	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2753	  hardware security vulnerability and its exploitation takes advantage
2754	  of speculative execution in a similar way to the Meltdown and Spectre
2755	  security vulnerabilities.
2756
2757endif
2758
2759config ARCH_HAS_ADD_PAGES
2760	def_bool y
2761	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2762
2763menu "Power management and ACPI options"
2764
2765config ARCH_HIBERNATION_HEADER
2766	def_bool y
2767	depends on HIBERNATION
2768
2769source "kernel/power/Kconfig"
2770
2771source "drivers/acpi/Kconfig"
2772
2773config X86_APM_BOOT
2774	def_bool y
2775	depends on APM
2776
2777menuconfig APM
2778	tristate "APM (Advanced Power Management) BIOS support"
2779	depends on X86_32 && PM_SLEEP
2780	help
2781	  APM is a BIOS specification for saving power using several different
2782	  techniques. This is mostly useful for battery powered laptops with
2783	  APM compliant BIOSes. If you say Y here, the system time will be
2784	  reset after a RESUME operation, the /proc/apm device will provide
2785	  battery status information, and user-space programs will receive
2786	  notification of APM "events" (e.g. battery status change).
2787
2788	  If you select "Y" here, you can disable actual use of the APM
2789	  BIOS by passing the "apm=off" option to the kernel at boot time.
2790
2791	  Note that the APM support is almost completely disabled for
2792	  machines with more than one CPU.
2793
2794	  In order to use APM, you will need supporting software. For location
2795	  and more information, read <file:Documentation/power/apm-acpi.rst>
2796	  and the Battery Powered Linux mini-HOWTO, available from
2797	  <http://www.tldp.org/docs.html#howto>.
2798
2799	  This driver does not spin down disk drives (see the hdparm(8)
2800	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2801	  VESA-compliant "green" monitors.
2802
2803	  This driver does not support the TI 4000M TravelMate and the ACER
2804	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2805	  desktop machines also don't have compliant BIOSes, and this driver
2806	  may cause those machines to panic during the boot phase.
2807
2808	  Generally, if you don't have a battery in your machine, there isn't
2809	  much point in using this driver and you should say N. If you get
2810	  random kernel OOPSes or reboots that don't seem to be related to
2811	  anything, try disabling/enabling this option (or disabling/enabling
2812	  APM in your BIOS).
2813
2814	  Some other things you should try when experiencing seemingly random,
2815	  "weird" problems:
2816
2817	  1) make sure that you have enough swap space and that it is
2818	  enabled.
2819	  2) pass the "idle=poll" option to the kernel
2820	  3) switch on floating point emulation in the kernel and pass
2821	  the "no387" option to the kernel
2822	  4) pass the "floppy=nodma" option to the kernel
2823	  5) pass the "mem=4M" option to the kernel (thereby disabling
2824	  all but the first 4 MB of RAM)
2825	  6) make sure that the CPU is not over clocked.
2826	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2827	  8) disable the cache from your BIOS settings
2828	  9) install a fan for the video card or exchange video RAM
2829	  10) install a better fan for the CPU
2830	  11) exchange RAM chips
2831	  12) exchange the motherboard.
2832
2833	  To compile this driver as a module, choose M here: the
2834	  module will be called apm.
2835
2836if APM
2837
2838config APM_IGNORE_USER_SUSPEND
2839	bool "Ignore USER SUSPEND"
2840	help
2841	  This option will ignore USER SUSPEND requests. On machines with a
2842	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2843	  series notebooks, it is necessary to say Y because of a BIOS bug.
2844
2845config APM_DO_ENABLE
2846	bool "Enable PM at boot time"
2847	help
2848	  Enable APM features at boot time. From page 36 of the APM BIOS
2849	  specification: "When disabled, the APM BIOS does not automatically
2850	  power manage devices, enter the Standby State, enter the Suspend
2851	  State, or take power saving steps in response to CPU Idle calls."
2852	  This driver will make CPU Idle calls when Linux is idle (unless this
2853	  feature is turned off -- see "Do CPU IDLE calls", below). This
2854	  should always save battery power, but more complicated APM features
2855	  will be dependent on your BIOS implementation. You may need to turn
2856	  this option off if your computer hangs at boot time when using APM
2857	  support, or if it beeps continuously instead of suspending. Turn
2858	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2859	  T400CDT. This is off by default since most machines do fine without
2860	  this feature.
2861
2862config APM_CPU_IDLE
2863	depends on CPU_IDLE
2864	bool "Make CPU Idle calls when idle"
2865	help
2866	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2867	  On some machines, this can activate improved power savings, such as
2868	  a slowed CPU clock rate, when the machine is idle. These idle calls
2869	  are made after the idle loop has run for some length of time (e.g.,
2870	  333 mS). On some machines, this will cause a hang at boot time or
2871	  whenever the CPU becomes idle. (On machines with more than one CPU,
2872	  this option does nothing.)
2873
2874config APM_DISPLAY_BLANK
2875	bool "Enable console blanking using APM"
2876	help
2877	  Enable console blanking using the APM. Some laptops can use this to
2878	  turn off the LCD backlight when the screen blanker of the Linux
2879	  virtual console blanks the screen. Note that this is only used by
2880	  the virtual console screen blanker, and won't turn off the backlight
2881	  when using the X Window system. This also doesn't have anything to
2882	  do with your VESA-compliant power-saving monitor. Further, this
2883	  option doesn't work for all laptops -- it might not turn off your
2884	  backlight at all, or it might print a lot of errors to the console,
2885	  especially if you are using gpm.
2886
2887config APM_ALLOW_INTS
2888	bool "Allow interrupts during APM BIOS calls"
2889	help
2890	  Normally we disable external interrupts while we are making calls to
2891	  the APM BIOS as a measure to lessen the effects of a badly behaving
2892	  BIOS implementation.  The BIOS should reenable interrupts if it
2893	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2894	  many of the newer IBM Thinkpads.  If you experience hangs when you
2895	  suspend, try setting this to Y.  Otherwise, say N.
2896
2897endif # APM
2898
2899source "drivers/cpufreq/Kconfig"
2900
2901source "drivers/cpuidle/Kconfig"
2902
2903source "drivers/idle/Kconfig"
2904
2905endmenu
2906
2907menu "Bus options (PCI etc.)"
2908
2909choice
2910	prompt "PCI access mode"
2911	depends on X86_32 && PCI
2912	default PCI_GOANY
2913	help
2914	  On PCI systems, the BIOS can be used to detect the PCI devices and
2915	  determine their configuration. However, some old PCI motherboards
2916	  have BIOS bugs and may crash if this is done. Also, some embedded
2917	  PCI-based systems don't have any BIOS at all. Linux can also try to
2918	  detect the PCI hardware directly without using the BIOS.
2919
2920	  With this option, you can specify how Linux should detect the
2921	  PCI devices. If you choose "BIOS", the BIOS will be used,
2922	  if you choose "Direct", the BIOS won't be used, and if you
2923	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2924	  If you choose "Any", the kernel will try MMCONFIG, then the
2925	  direct access method and falls back to the BIOS if that doesn't
2926	  work. If unsure, go with the default, which is "Any".
2927
2928config PCI_GOBIOS
2929	bool "BIOS"
2930
2931config PCI_GOMMCONFIG
2932	bool "MMConfig"
2933
2934config PCI_GODIRECT
2935	bool "Direct"
2936
2937config PCI_GOOLPC
2938	bool "OLPC XO-1"
2939	depends on OLPC
2940
2941config PCI_GOANY
2942	bool "Any"
2943
2944endchoice
2945
2946config PCI_BIOS
2947	def_bool y
2948	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2949
2950# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2951config PCI_DIRECT
2952	def_bool y
2953	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2954
2955config PCI_MMCONFIG
2956	bool "Support mmconfig PCI config space access" if X86_64
2957	default y
2958	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2959	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2960
2961config PCI_OLPC
2962	def_bool y
2963	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2964
2965config PCI_XEN
2966	def_bool y
2967	depends on PCI && XEN
2968
2969config MMCONF_FAM10H
2970	def_bool y
2971	depends on X86_64 && PCI_MMCONFIG && ACPI
2972
2973config PCI_CNB20LE_QUIRK
2974	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2975	depends on PCI
2976	help
2977	  Read the PCI windows out of the CNB20LE host bridge. This allows
2978	  PCI hotplug to work on systems with the CNB20LE chipset which do
2979	  not have ACPI.
2980
2981	  There's no public spec for this chipset, and this functionality
2982	  is known to be incomplete.
2983
2984	  You should say N unless you know you need this.
2985
2986config ISA_BUS
2987	bool "ISA bus support on modern systems" if EXPERT
2988	help
2989	  Expose ISA bus device drivers and options available for selection and
2990	  configuration. Enable this option if your target machine has an ISA
2991	  bus. ISA is an older system, displaced by PCI and newer bus
2992	  architectures -- if your target machine is modern, it probably does
2993	  not have an ISA bus.
2994
2995	  If unsure, say N.
2996
2997# x86_64 have no ISA slots, but can have ISA-style DMA.
2998config ISA_DMA_API
2999	bool "ISA-style DMA support" if (X86_64 && EXPERT)
3000	default y
3001	help
3002	  Enables ISA-style DMA support for devices requiring such controllers.
3003	  If unsure, say Y.
3004
3005if X86_32
3006
3007config ISA
3008	bool "ISA support"
3009	help
3010	  Find out whether you have ISA slots on your motherboard.  ISA is the
3011	  name of a bus system, i.e. the way the CPU talks to the other stuff
3012	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
3013	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
3014	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
3015
3016config SCx200
3017	tristate "NatSemi SCx200 support"
3018	help
3019	  This provides basic support for National Semiconductor's
3020	  (now AMD's) Geode processors.  The driver probes for the
3021	  PCI-IDs of several on-chip devices, so its a good dependency
3022	  for other scx200_* drivers.
3023
3024	  If compiled as a module, the driver is named scx200.
3025
3026config SCx200HR_TIMER
3027	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
3028	depends on SCx200
3029	default y
3030	help
3031	  This driver provides a clocksource built upon the on-chip
3032	  27MHz high-resolution timer.  Its also a workaround for
3033	  NSC Geode SC-1100's buggy TSC, which loses time when the
3034	  processor goes idle (as is done by the scheduler).  The
3035	  other workaround is idle=poll boot option.
3036
3037config OLPC
3038	bool "One Laptop Per Child support"
3039	depends on !X86_PAE
3040	select GPIOLIB
3041	select OF
3042	select OF_PROMTREE
3043	select IRQ_DOMAIN
3044	select OLPC_EC
3045	help
3046	  Add support for detecting the unique features of the OLPC
3047	  XO hardware.
3048
3049config OLPC_XO1_PM
3050	bool "OLPC XO-1 Power Management"
3051	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3052	help
3053	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3054
3055config OLPC_XO1_RTC
3056	bool "OLPC XO-1 Real Time Clock"
3057	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3058	help
3059	  Add support for the XO-1 real time clock, which can be used as a
3060	  programmable wakeup source.
3061
3062config OLPC_XO1_SCI
3063	bool "OLPC XO-1 SCI extras"
3064	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3065	depends on INPUT=y
3066	select POWER_SUPPLY
3067	help
3068	  Add support for SCI-based features of the OLPC XO-1 laptop:
3069	   - EC-driven system wakeups
3070	   - Power button
3071	   - Ebook switch
3072	   - Lid switch
3073	   - AC adapter status updates
3074	   - Battery status updates
3075
3076config OLPC_XO15_SCI
3077	bool "OLPC XO-1.5 SCI extras"
3078	depends on OLPC && ACPI
3079	select POWER_SUPPLY
3080	help
3081	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3082	   - EC-driven system wakeups
3083	   - AC adapter status updates
3084	   - Battery status updates
3085
3086config GEODE_COMMON
3087	bool
3088
3089config ALIX
3090	bool "PCEngines ALIX System Support (LED setup)"
3091	select GPIOLIB
3092	select GEODE_COMMON
3093	help
3094	  This option enables system support for the PCEngines ALIX.
3095	  At present this just sets up LEDs for GPIO control on
3096	  ALIX2/3/6 boards.  However, other system specific setup should
3097	  get added here.
3098
3099	  Note: You must still enable the drivers for GPIO and LED support
3100	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3101
3102	  Note: You have to set alix.force=1 for boards with Award BIOS.
3103
3104config NET5501
3105	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3106	select GPIOLIB
3107	select GEODE_COMMON
3108	help
3109	  This option enables system support for the Soekris Engineering net5501.
3110
3111config GEOS
3112	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3113	select GPIOLIB
3114	select GEODE_COMMON
3115	depends on DMI
3116	help
3117	  This option enables system support for the Traverse Technologies GEOS.
3118
3119config TS5500
3120	bool "Technologic Systems TS-5500 platform support"
3121	depends on MELAN
3122	select CHECK_SIGNATURE
3123	select NEW_LEDS
3124	select LEDS_CLASS
3125	help
3126	  This option enables system support for the Technologic Systems TS-5500.
3127
3128endif # X86_32
3129
3130config AMD_NB
3131	def_bool y
3132	depends on CPU_SUP_AMD && PCI
3133
3134endmenu
3135
3136menu "Binary Emulations"
3137
3138config IA32_EMULATION
3139	bool "IA32 Emulation"
3140	depends on X86_64
3141	select ARCH_WANT_OLD_COMPAT_IPC
3142	select BINFMT_ELF
3143	select COMPAT_OLD_SIGACTION
3144	help
3145	  Include code to run legacy 32-bit programs under a
3146	  64-bit kernel. You should likely turn this on, unless you're
3147	  100% sure that you don't have any 32-bit programs left.
3148
3149config IA32_EMULATION_DEFAULT_DISABLED
3150	bool "IA32 emulation disabled by default"
3151	default n
3152	depends on IA32_EMULATION
3153	help
3154	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3155	  processes and access to 32-bit syscalls. If unsure, leave it to its
3156	  default value.
3157
3158config X86_X32_ABI
3159	bool "x32 ABI for 64-bit mode"
3160	depends on X86_64
3161	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3162	# compressed debug sections to x86_x32 properly:
3163	# https://github.com/ClangBuiltLinux/linux/issues/514
3164	# https://github.com/ClangBuiltLinux/linux/issues/1141
3165	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3166	help
3167	  Include code to run binaries for the x32 native 32-bit ABI
3168	  for 64-bit processors.  An x32 process gets access to the
3169	  full 64-bit register file and wide data path while leaving
3170	  pointers at 32 bits for smaller memory footprint.
3171
3172config COMPAT_32
3173	def_bool y
3174	depends on IA32_EMULATION || X86_32
3175	select HAVE_UID16
3176	select OLD_SIGSUSPEND3
3177
3178config COMPAT
3179	def_bool y
3180	depends on IA32_EMULATION || X86_X32_ABI
3181
3182config COMPAT_FOR_U64_ALIGNMENT
3183	def_bool y
3184	depends on COMPAT
3185
3186endmenu
3187
3188config HAVE_ATOMIC_IOMAP
3189	def_bool y
3190	depends on X86_32
3191
3192source "arch/x86/kvm/Kconfig"
3193
3194source "arch/x86/Kconfig.assembler"
3195