xref: /linux/arch/x86/Kconfig (revision 8a3dc0f7c4ccf13098dba804be06799b4bd46c7a)
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_CRC32
80	select ARCH_HAS_CRC_T10DIF		if X86_64
81	select ARCH_HAS_CURRENT_STACK_POINTER
82	select ARCH_HAS_DEBUG_VIRTUAL
83	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
84	select ARCH_HAS_DEVMEM_IS_ALLOWED
85	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
86	select ARCH_HAS_EARLY_DEBUG		if KGDB
87	select ARCH_HAS_ELF_RANDOMIZE
88	select ARCH_HAS_EXECMEM_ROX		if X86_64
89	select ARCH_HAS_FAST_MULTIPLIER
90	select ARCH_HAS_FORTIFY_SOURCE
91	select ARCH_HAS_GCOV_PROFILE_ALL
92	select ARCH_HAS_KCOV			if X86_64
93	select ARCH_HAS_KERNEL_FPU_SUPPORT
94	select ARCH_HAS_MEM_ENCRYPT
95	select ARCH_HAS_MEMBARRIER_SYNC_CORE
96	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
97	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
98	select ARCH_HAS_PMEM_API		if X86_64
99	select ARCH_HAS_PREEMPT_LAZY
100	select ARCH_HAS_PTE_DEVMAP		if X86_64
101	select ARCH_HAS_PTE_SPECIAL
102	select ARCH_HAS_HW_PTE_YOUNG
103	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
104	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
105	select ARCH_HAS_COPY_MC			if X86_64
106	select ARCH_HAS_SET_MEMORY
107	select ARCH_HAS_SET_DIRECT_MAP
108	select ARCH_HAS_STRICT_KERNEL_RWX
109	select ARCH_HAS_STRICT_MODULE_RWX
110	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
111	select ARCH_HAS_SYSCALL_WRAPPER
112	select ARCH_HAS_UBSAN
113	select ARCH_HAS_DEBUG_WX
114	select ARCH_HAS_ZONE_DMA_SET if EXPERT
115	select ARCH_HAVE_NMI_SAFE_CMPXCHG
116	select ARCH_HAVE_EXTRA_ELF_NOTES
117	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
118	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
119	select ARCH_MIGHT_HAVE_PC_PARPORT
120	select ARCH_MIGHT_HAVE_PC_SERIO
121	select ARCH_STACKWALK
122	select ARCH_SUPPORTS_ACPI
123	select ARCH_SUPPORTS_ATOMIC_RMW
124	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
125	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
126	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
127	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
128	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
129	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
130	select ARCH_SUPPORTS_LTO_CLANG
131	select ARCH_SUPPORTS_LTO_CLANG_THIN
132	select ARCH_SUPPORTS_RT
133	select ARCH_SUPPORTS_AUTOFDO_CLANG
134	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
135	select ARCH_USE_BUILTIN_BSWAP
136	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
137	select ARCH_USE_MEMTEST
138	select ARCH_USE_QUEUED_RWLOCKS
139	select ARCH_USE_QUEUED_SPINLOCKS
140	select ARCH_USE_SYM_ANNOTATIONS
141	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
142	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
143	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
144	select ARCH_WANTS_NO_INSTR
145	select ARCH_WANT_GENERAL_HUGETLB
146	select ARCH_WANT_HUGE_PMD_SHARE
147	select ARCH_WANT_LD_ORPHAN_WARN
148	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
149	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
150	select ARCH_WANTS_THP_SWAP		if X86_64
151	select ARCH_HAS_PARANOID_L1D_FLUSH
152	select BUILDTIME_TABLE_SORT
153	select CLKEVT_I8253
154	select CLOCKSOURCE_WATCHDOG
155	# Word-size accesses may read uninitialized data past the trailing \0
156	# in strings and cause false KMSAN reports.
157	select DCACHE_WORD_ACCESS		if !KMSAN
158	select DYNAMIC_SIGFRAME
159	select EDAC_ATOMIC_SCRUB
160	select EDAC_SUPPORT
161	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
162	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
163	select GENERIC_CLOCKEVENTS_MIN_ADJUST
164	select GENERIC_CMOS_UPDATE
165	select GENERIC_CPU_AUTOPROBE
166	select GENERIC_CPU_DEVICES
167	select GENERIC_CPU_VULNERABILITIES
168	select GENERIC_EARLY_IOREMAP
169	select GENERIC_ENTRY
170	select GENERIC_IOMAP
171	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
172	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
173	select GENERIC_IRQ_MIGRATION		if SMP
174	select GENERIC_IRQ_PROBE
175	select GENERIC_IRQ_RESERVATION_MODE
176	select GENERIC_IRQ_SHOW
177	select GENERIC_PENDING_IRQ		if SMP
178	select GENERIC_PTDUMP
179	select GENERIC_SMP_IDLE_THREAD
180	select GENERIC_TIME_VSYSCALL
181	select GENERIC_GETTIMEOFDAY
182	select GENERIC_VDSO_TIME_NS
183	select GENERIC_VDSO_OVERFLOW_PROTECT
184	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
185	select HARDIRQS_SW_RESEND
186	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
187	select HAS_IOPORT
188	select HAVE_ACPI_APEI			if ACPI
189	select HAVE_ACPI_APEI_NMI		if ACPI
190	select HAVE_ALIGNED_STRUCT_PAGE
191	select HAVE_ARCH_AUDITSYSCALL
192	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
193	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
194	select HAVE_ARCH_JUMP_LABEL
195	select HAVE_ARCH_JUMP_LABEL_RELATIVE
196	select HAVE_ARCH_KASAN			if X86_64
197	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
198	select HAVE_ARCH_KFENCE
199	select HAVE_ARCH_KMSAN			if X86_64
200	select HAVE_ARCH_KGDB
201	select HAVE_ARCH_MMAP_RND_BITS		if MMU
202	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
203	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
204	select HAVE_ARCH_PREL32_RELOCATIONS
205	select HAVE_ARCH_SECCOMP_FILTER
206	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
207	select HAVE_ARCH_STACKLEAK
208	select HAVE_ARCH_TRACEHOOK
209	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
210	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
211	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
212	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
213	select HAVE_ARCH_VMAP_STACK		if X86_64
214	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
215	select HAVE_ARCH_WITHIN_STACK_FRAMES
216	select HAVE_ASM_MODVERSIONS
217	select HAVE_CMPXCHG_DOUBLE
218	select HAVE_CMPXCHG_LOCAL
219	select HAVE_CONTEXT_TRACKING_USER		if X86_64
220	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
221	select HAVE_C_RECORDMCOUNT
222	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
223	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
224	select HAVE_BUILDTIME_MCOUNT_SORT
225	select HAVE_DEBUG_KMEMLEAK
226	select HAVE_DMA_CONTIGUOUS
227	select HAVE_DYNAMIC_FTRACE
228	select HAVE_DYNAMIC_FTRACE_WITH_REGS
229	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
230	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
231	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
232	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
233	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
234	select HAVE_EBPF_JIT
235	select HAVE_EFFICIENT_UNALIGNED_ACCESS
236	select HAVE_EISA			if X86_32
237	select HAVE_EXIT_THREAD
238	select HAVE_GUP_FAST
239	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
240	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
241	select HAVE_FTRACE_MCOUNT_RECORD
242	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
243	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
244	select HAVE_FUNCTION_TRACER
245	select HAVE_GCC_PLUGINS
246	select HAVE_HW_BREAKPOINT
247	select HAVE_IOREMAP_PROT
248	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
249	select HAVE_IRQ_TIME_ACCOUNTING
250	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
251	select HAVE_KERNEL_BZIP2
252	select HAVE_KERNEL_GZIP
253	select HAVE_KERNEL_LZ4
254	select HAVE_KERNEL_LZMA
255	select HAVE_KERNEL_LZO
256	select HAVE_KERNEL_XZ
257	select HAVE_KERNEL_ZSTD
258	select HAVE_KPROBES
259	select HAVE_KPROBES_ON_FTRACE
260	select HAVE_FUNCTION_ERROR_INJECTION
261	select HAVE_KRETPROBES
262	select HAVE_RETHOOK
263	select HAVE_LIVEPATCH			if X86_64
264	select HAVE_MIXED_BREAKPOINTS_REGS
265	select HAVE_MOD_ARCH_SPECIFIC
266	select HAVE_MOVE_PMD
267	select HAVE_MOVE_PUD
268	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
269	select HAVE_NMI
270	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
271	select HAVE_OBJTOOL			if X86_64
272	select HAVE_OPTPROBES
273	select HAVE_PAGE_SIZE_4KB
274	select HAVE_PCSPKR_PLATFORM
275	select HAVE_PERF_EVENTS
276	select HAVE_PERF_EVENTS_NMI
277	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
278	select HAVE_PCI
279	select HAVE_PERF_REGS
280	select HAVE_PERF_USER_STACK_DUMP
281	select MMU_GATHER_RCU_TABLE_FREE
282	select MMU_GATHER_MERGE_VMAS
283	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
284	select HAVE_REGS_AND_STACK_ACCESS_API
285	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
286	select HAVE_FUNCTION_ARG_ACCESS_API
287	select HAVE_SETUP_PER_CPU_AREA
288	select HAVE_SOFTIRQ_ON_OWN_STACK
289	select HAVE_STACKPROTECTOR
290	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
291	select HAVE_STATIC_CALL
292	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
293	select HAVE_PREEMPT_DYNAMIC_CALL
294	select HAVE_RSEQ
295	select HAVE_RUST			if X86_64
296	select HAVE_SYSCALL_TRACEPOINTS
297	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
298	select HAVE_UNSTABLE_SCHED_CLOCK
299	select HAVE_USER_RETURN_NOTIFIER
300	select HAVE_GENERIC_VDSO
301	select VDSO_GETRANDOM			if X86_64
302	select HOTPLUG_PARALLEL			if SMP && X86_64
303	select HOTPLUG_SMT			if SMP
304	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
305	select IRQ_FORCED_THREADING
306	select LOCK_MM_AND_FIND_VMA
307	select NEED_PER_CPU_EMBED_FIRST_CHUNK
308	select NEED_PER_CPU_PAGE_FIRST_CHUNK
309	select NEED_SG_DMA_LENGTH
310	select NUMA_MEMBLKS			if NUMA
311	select PCI_DOMAINS			if PCI
312	select PCI_LOCKLESS_CONFIG		if PCI
313	select PERF_EVENTS
314	select RTC_LIB
315	select RTC_MC146818_LIB
316	select SPARSE_IRQ
317	select SYSCTL_EXCEPTION_TRACE
318	select THREAD_INFO_IN_TASK
319	select TRACE_IRQFLAGS_SUPPORT
320	select TRACE_IRQFLAGS_NMI_SUPPORT
321	select USER_STACKTRACE_SUPPORT
322	select HAVE_ARCH_KCSAN			if X86_64
323	select PROC_PID_ARCH_STATUS		if PROC_FS
324	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
325	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
326	select FUNCTION_ALIGNMENT_4B
327	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
328	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
329	select ARCH_SUPPORTS_PT_RECLAIM		if X86_64
330
331config INSTRUCTION_DECODER
332	def_bool y
333	depends on KPROBES || PERF_EVENTS || UPROBES
334
335config OUTPUT_FORMAT
336	string
337	default "elf32-i386" if X86_32
338	default "elf64-x86-64" if X86_64
339
340config LOCKDEP_SUPPORT
341	def_bool y
342
343config STACKTRACE_SUPPORT
344	def_bool y
345
346config MMU
347	def_bool y
348
349config ARCH_MMAP_RND_BITS_MIN
350	default 28 if 64BIT
351	default 8
352
353config ARCH_MMAP_RND_BITS_MAX
354	default 32 if 64BIT
355	default 16
356
357config ARCH_MMAP_RND_COMPAT_BITS_MIN
358	default 8
359
360config ARCH_MMAP_RND_COMPAT_BITS_MAX
361	default 16
362
363config SBUS
364	bool
365
366config GENERIC_ISA_DMA
367	def_bool y
368	depends on ISA_DMA_API
369
370config GENERIC_CSUM
371	bool
372	default y if KMSAN || KASAN
373
374config GENERIC_BUG
375	def_bool y
376	depends on BUG
377	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
378
379config GENERIC_BUG_RELATIVE_POINTERS
380	bool
381
382config ARCH_MAY_HAVE_PC_FDC
383	def_bool y
384	depends on ISA_DMA_API
385
386config GENERIC_CALIBRATE_DELAY
387	def_bool y
388
389config ARCH_HAS_CPU_RELAX
390	def_bool y
391
392config ARCH_HIBERNATION_POSSIBLE
393	def_bool y
394
395config ARCH_SUSPEND_POSSIBLE
396	def_bool y
397
398config AUDIT_ARCH
399	def_bool y if X86_64
400
401config KASAN_SHADOW_OFFSET
402	hex
403	depends on KASAN
404	default 0xdffffc0000000000
405
406config HAVE_INTEL_TXT
407	def_bool y
408	depends on INTEL_IOMMU && ACPI
409
410config X86_64_SMP
411	def_bool y
412	depends on X86_64 && SMP
413
414config ARCH_SUPPORTS_UPROBES
415	def_bool y
416
417config FIX_EARLYCON_MEM
418	def_bool y
419
420config DYNAMIC_PHYSICAL_MASK
421	bool
422
423config PGTABLE_LEVELS
424	int
425	default 5 if X86_5LEVEL
426	default 4 if X86_64
427	default 3 if X86_PAE
428	default 2
429
430menu "Processor type and features"
431
432config SMP
433	bool "Symmetric multi-processing support"
434	help
435	  This enables support for systems with more than one CPU. If you have
436	  a system with only one CPU, say N. If you have a system with more
437	  than one CPU, say Y.
438
439	  If you say N here, the kernel will run on uni- and multiprocessor
440	  machines, but will use only one CPU of a multiprocessor machine. If
441	  you say Y here, the kernel will run on many, but not all,
442	  uniprocessor machines. On a uniprocessor machine, the kernel
443	  will run faster if you say N here.
444
445	  Note that if you say Y here and choose architecture "586" or
446	  "Pentium" under "Processor family", the kernel will not work on 486
447	  architectures. Similarly, multiprocessor kernels for the "PPro"
448	  architecture may not work on all Pentium based boards.
449
450	  People using multiprocessor machines who say Y here should also say
451	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
452	  Management" code will be disabled if you say Y here.
453
454	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
455	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
456	  <http://www.tldp.org/docs.html#howto>.
457
458	  If you don't know what to do here, say N.
459
460config X86_X2APIC
461	bool "Support x2apic"
462	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
463	help
464	  This enables x2apic support on CPUs that have this feature.
465
466	  This allows 32-bit apic IDs (so it can support very large systems),
467	  and accesses the local apic via MSRs not via mmio.
468
469	  Some Intel systems circa 2022 and later are locked into x2APIC mode
470	  and can not fall back to the legacy APIC modes if SGX or TDX are
471	  enabled in the BIOS. They will boot with very reduced functionality
472	  without enabling this option.
473
474	  If you don't know what to do here, say N.
475
476config X86_POSTED_MSI
477	bool "Enable MSI and MSI-x delivery by posted interrupts"
478	depends on X86_64 && IRQ_REMAP
479	help
480	  This enables MSIs that are under interrupt remapping to be delivered as
481	  posted interrupts to the host kernel. Interrupt throughput can
482	  potentially be improved by coalescing CPU notifications during high
483	  frequency bursts.
484
485	  If you don't know what to do here, say N.
486
487config X86_MPPARSE
488	bool "Enable MPS table" if ACPI
489	default y
490	depends on X86_LOCAL_APIC
491	help
492	  For old smp systems that do not have proper acpi support. Newer systems
493	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
494
495config X86_CPU_RESCTRL
496	bool "x86 CPU resource control support"
497	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
498	select KERNFS
499	select PROC_CPU_RESCTRL		if PROC_FS
500	help
501	  Enable x86 CPU resource control support.
502
503	  Provide support for the allocation and monitoring of system resources
504	  usage by the CPU.
505
506	  Intel calls this Intel Resource Director Technology
507	  (Intel(R) RDT). More information about RDT can be found in the
508	  Intel x86 Architecture Software Developer Manual.
509
510	  AMD calls this AMD Platform Quality of Service (AMD QoS).
511	  More information about AMD QoS can be found in the AMD64 Technology
512	  Platform Quality of Service Extensions manual.
513
514	  Say N if unsure.
515
516config X86_FRED
517	bool "Flexible Return and Event Delivery"
518	depends on X86_64
519	help
520	  When enabled, try to use Flexible Return and Event Delivery
521	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
522	  ring transitions and exception/interrupt handling if the
523	  system supports it.
524
525config X86_EXTENDED_PLATFORM
526	bool "Support for extended (non-PC) x86 platforms"
527	default y
528	help
529	  If you disable this option then the kernel will only support
530	  standard PC platforms. (which covers the vast majority of
531	  systems out there.)
532
533	  If you enable this option then you'll be able to select support
534	  for the following non-PC x86 platforms, depending on the value of
535	  CONFIG_64BIT.
536
537	  32-bit platforms (CONFIG_64BIT=n):
538		Goldfish (Android emulator)
539		AMD Elan
540		RDC R-321x SoC
541		SGI 320/540 (Visual Workstation)
542
543	  64-bit platforms (CONFIG_64BIT=y):
544		Numascale NumaChip
545		ScaleMP vSMP
546		SGI Ultraviolet
547		Merrifield/Moorefield MID devices
548
549	  If you have one of these systems, or if you want to build a
550	  generic distribution kernel, say Y here - otherwise say N.
551
552# This is an alphabetically sorted list of 64 bit extended platforms
553# Please maintain the alphabetic order if and when there are additions
554config X86_NUMACHIP
555	bool "Numascale NumaChip"
556	depends on X86_64
557	depends on X86_EXTENDED_PLATFORM
558	depends on NUMA
559	depends on SMP
560	depends on X86_X2APIC
561	depends on PCI_MMCONFIG
562	help
563	  Adds support for Numascale NumaChip large-SMP systems. Needed to
564	  enable more than ~168 cores.
565	  If you don't have one of these, you should say N here.
566
567config X86_VSMP
568	bool "ScaleMP vSMP"
569	select HYPERVISOR_GUEST
570	select PARAVIRT
571	depends on X86_64 && PCI
572	depends on X86_EXTENDED_PLATFORM
573	depends on SMP
574	help
575	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
576	  supposed to run on these EM64T-based machines.  Only choose this option
577	  if you have one of these machines.
578
579config X86_UV
580	bool "SGI Ultraviolet"
581	depends on X86_64
582	depends on X86_EXTENDED_PLATFORM
583	depends on NUMA
584	depends on EFI
585	depends on KEXEC_CORE
586	depends on X86_X2APIC
587	depends on PCI
588	help
589	  This option is needed in order to support SGI Ultraviolet systems.
590	  If you don't have one of these, you should say N here.
591
592config X86_INTEL_MID
593	bool "Intel Z34xx/Z35xx MID platform support"
594	depends on X86_EXTENDED_PLATFORM
595	depends on X86_PLATFORM_DEVICES
596	depends on PCI
597	depends on X86_64 || (EXPERT && PCI_GOANY)
598	depends on X86_IO_APIC
599	select I2C
600	select DW_APB_TIMER
601	select INTEL_SCU_PCI
602	help
603	  Select to build a kernel capable of supporting 64-bit Intel MID
604	  (Mobile Internet Device) platform systems which do not have
605	  the PCI legacy interfaces.
606
607	  The only supported devices are the 22nm Merrified (Z34xx)
608	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
609	  a small number of Android devices such as the Asus Zenfone 2,
610	  Asus FonePad 8 and Dell Venue 7.
611
612	  If you are building for a PC class system or non-MID tablet
613	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
614
615	  Intel MID platforms are based on an Intel processor and chipset which
616	  consume less power than most of the x86 derivatives.
617
618config X86_GOLDFISH
619	bool "Goldfish (Virtual Platform)"
620	depends on X86_EXTENDED_PLATFORM
621	help
622	  Enable support for the Goldfish virtual platform used primarily
623	  for Android development. Unless you are building for the Android
624	  Goldfish emulator say N here.
625
626# Following is an alphabetically sorted list of 32 bit extended platforms
627# Please maintain the alphabetic order if and when there are additions
628
629config X86_INTEL_CE
630	bool "CE4100 TV platform"
631	depends on PCI
632	depends on PCI_GODIRECT
633	depends on X86_IO_APIC
634	depends on X86_32
635	depends on X86_EXTENDED_PLATFORM
636	select X86_REBOOTFIXUPS
637	select OF
638	select OF_EARLY_FLATTREE
639	help
640	  Select for the Intel CE media processor (CE4100) SOC.
641	  This option compiles in support for the CE4100 SOC for settop
642	  boxes and media devices.
643
644config X86_INTEL_QUARK
645	bool "Intel Quark platform support"
646	depends on X86_32
647	depends on X86_EXTENDED_PLATFORM
648	depends on X86_PLATFORM_DEVICES
649	depends on X86_TSC
650	depends on PCI
651	depends on PCI_GOANY
652	depends on X86_IO_APIC
653	select IOSF_MBI
654	select INTEL_IMR
655	select COMMON_CLK
656	help
657	  Select to include support for Quark X1000 SoC.
658	  Say Y here if you have a Quark based system such as the Arduino
659	  compatible Intel Galileo.
660
661config X86_INTEL_LPSS
662	bool "Intel Low Power Subsystem Support"
663	depends on X86 && ACPI && PCI
664	select COMMON_CLK
665	select PINCTRL
666	select IOSF_MBI
667	help
668	  Select to build support for Intel Low Power Subsystem such as
669	  found on Intel Lynxpoint PCH. Selecting this option enables
670	  things like clock tree (common clock framework) and pincontrol
671	  which are needed by the LPSS peripheral drivers.
672
673config X86_AMD_PLATFORM_DEVICE
674	bool "AMD ACPI2Platform devices support"
675	depends on ACPI
676	select COMMON_CLK
677	select PINCTRL
678	help
679	  Select to interpret AMD specific ACPI device to platform device
680	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
681	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
682	  implemented under PINCTRL subsystem.
683
684config IOSF_MBI
685	tristate "Intel SoC IOSF Sideband support for SoC platforms"
686	depends on PCI
687	help
688	  This option enables sideband register access support for Intel SoC
689	  platforms. On these platforms the IOSF sideband is used in lieu of
690	  MSR's for some register accesses, mostly but not limited to thermal
691	  and power. Drivers may query the availability of this device to
692	  determine if they need the sideband in order to work on these
693	  platforms. The sideband is available on the following SoC products.
694	  This list is not meant to be exclusive.
695	   - BayTrail
696	   - Braswell
697	   - Quark
698
699	  You should say Y if you are running a kernel on one of these SoC's.
700
701config IOSF_MBI_DEBUG
702	bool "Enable IOSF sideband access through debugfs"
703	depends on IOSF_MBI && DEBUG_FS
704	help
705	  Select this option to expose the IOSF sideband access registers (MCR,
706	  MDR, MCRX) through debugfs to write and read register information from
707	  different units on the SoC. This is most useful for obtaining device
708	  state information for debug and analysis. As this is a general access
709	  mechanism, users of this option would have specific knowledge of the
710	  device they want to access.
711
712	  If you don't require the option or are in doubt, say N.
713
714config X86_RDC321X
715	bool "RDC R-321x SoC"
716	depends on X86_32
717	depends on X86_EXTENDED_PLATFORM
718	select M486
719	select X86_REBOOTFIXUPS
720	help
721	  This option is needed for RDC R-321x system-on-chip, also known
722	  as R-8610-(G).
723	  If you don't have one of these chips, you should say N here.
724
725config X86_SUPPORTS_MEMORY_FAILURE
726	def_bool y
727	# MCE code calls memory_failure():
728	depends on X86_MCE
729	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
730	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
731	depends on X86_64 || !SPARSEMEM
732	select ARCH_SUPPORTS_MEMORY_FAILURE
733
734config X86_32_IRIS
735	tristate "Eurobraille/Iris poweroff module"
736	depends on X86_32
737	help
738	  The Iris machines from EuroBraille do not have APM or ACPI support
739	  to shut themselves down properly.  A special I/O sequence is
740	  needed to do so, which is what this module does at
741	  kernel shutdown.
742
743	  This is only for Iris machines from EuroBraille.
744
745	  If unused, say N.
746
747config SCHED_OMIT_FRAME_POINTER
748	def_bool y
749	prompt "Single-depth WCHAN output"
750	depends on X86
751	help
752	  Calculate simpler /proc/<PID>/wchan values. If this option
753	  is disabled then wchan values will recurse back to the
754	  caller function. This provides more accurate wchan values,
755	  at the expense of slightly more scheduling overhead.
756
757	  If in doubt, say "Y".
758
759menuconfig HYPERVISOR_GUEST
760	bool "Linux guest support"
761	help
762	  Say Y here to enable options for running Linux under various hyper-
763	  visors. This option enables basic hypervisor detection and platform
764	  setup.
765
766	  If you say N, all options in this submenu will be skipped and
767	  disabled, and Linux guest support won't be built in.
768
769if HYPERVISOR_GUEST
770
771config PARAVIRT
772	bool "Enable paravirtualization code"
773	depends on HAVE_STATIC_CALL
774	help
775	  This changes the kernel so it can modify itself when it is run
776	  under a hypervisor, potentially improving performance significantly
777	  over full virtualization.  However, when run without a hypervisor
778	  the kernel is theoretically slower and slightly larger.
779
780config PARAVIRT_XXL
781	bool
782
783config PARAVIRT_DEBUG
784	bool "paravirt-ops debugging"
785	depends on PARAVIRT && DEBUG_KERNEL
786	help
787	  Enable to debug paravirt_ops internals.  Specifically, BUG if
788	  a paravirt_op is missing when it is called.
789
790config PARAVIRT_SPINLOCKS
791	bool "Paravirtualization layer for spinlocks"
792	depends on PARAVIRT && SMP
793	help
794	  Paravirtualized spinlocks allow a pvops backend to replace the
795	  spinlock implementation with something virtualization-friendly
796	  (for example, block the virtual CPU rather than spinning).
797
798	  It has a minimal impact on native kernels and gives a nice performance
799	  benefit on paravirtualized KVM / Xen kernels.
800
801	  If you are unsure how to answer this question, answer Y.
802
803config X86_HV_CALLBACK_VECTOR
804	def_bool n
805
806source "arch/x86/xen/Kconfig"
807
808config KVM_GUEST
809	bool "KVM Guest support (including kvmclock)"
810	depends on PARAVIRT
811	select PARAVIRT_CLOCK
812	select ARCH_CPUIDLE_HALTPOLL
813	select X86_HV_CALLBACK_VECTOR
814	default y
815	help
816	  This option enables various optimizations for running under the KVM
817	  hypervisor. It includes a paravirtualized clock, so that instead
818	  of relying on a PIT (or probably other) emulation by the
819	  underlying device model, the host provides the guest with
820	  timing infrastructure such as time of day, and system time
821
822config ARCH_CPUIDLE_HALTPOLL
823	def_bool n
824	prompt "Disable host haltpoll when loading haltpoll driver"
825	help
826	  If virtualized under KVM, disable host haltpoll.
827
828config PVH
829	bool "Support for running PVH guests"
830	help
831	  This option enables the PVH entry point for guest virtual machines
832	  as specified in the x86/HVM direct boot ABI.
833
834config PARAVIRT_TIME_ACCOUNTING
835	bool "Paravirtual steal time accounting"
836	depends on PARAVIRT
837	help
838	  Select this option to enable fine granularity task steal time
839	  accounting. Time spent executing other tasks in parallel with
840	  the current vCPU is discounted from the vCPU power. To account for
841	  that, there can be a small performance impact.
842
843	  If in doubt, say N here.
844
845config PARAVIRT_CLOCK
846	bool
847
848config JAILHOUSE_GUEST
849	bool "Jailhouse non-root cell support"
850	depends on X86_64 && PCI
851	select X86_PM_TIMER
852	help
853	  This option allows to run Linux as guest in a Jailhouse non-root
854	  cell. You can leave this option disabled if you only want to start
855	  Jailhouse and run Linux afterwards in the root cell.
856
857config ACRN_GUEST
858	bool "ACRN Guest support"
859	depends on X86_64
860	select X86_HV_CALLBACK_VECTOR
861	help
862	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
863	  a flexible, lightweight reference open-source hypervisor, built with
864	  real-time and safety-criticality in mind. It is built for embedded
865	  IOT with small footprint and real-time features. More details can be
866	  found in https://projectacrn.org/.
867
868config INTEL_TDX_GUEST
869	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
870	depends on X86_64 && CPU_SUP_INTEL
871	depends on X86_X2APIC
872	depends on EFI_STUB
873	select ARCH_HAS_CC_PLATFORM
874	select X86_MEM_ENCRYPT
875	select X86_MCE
876	select UNACCEPTED_MEMORY
877	help
878	  Support running as a guest under Intel TDX.  Without this support,
879	  the guest kernel can not boot or run under TDX.
880	  TDX includes memory encryption and integrity capabilities
881	  which protect the confidentiality and integrity of guest
882	  memory contents and CPU state. TDX guests are protected from
883	  some attacks from the VMM.
884
885endif # HYPERVISOR_GUEST
886
887source "arch/x86/Kconfig.cpu"
888
889config HPET_TIMER
890	def_bool X86_64
891	prompt "HPET Timer Support" if X86_32
892	help
893	  Use the IA-PC HPET (High Precision Event Timer) to manage
894	  time in preference to the PIT and RTC, if a HPET is
895	  present.
896	  HPET is the next generation timer replacing legacy 8254s.
897	  The HPET provides a stable time base on SMP
898	  systems, unlike the TSC, but it is more expensive to access,
899	  as it is off-chip.  The interface used is documented
900	  in the HPET spec, revision 1.
901
902	  You can safely choose Y here.  However, HPET will only be
903	  activated if the platform and the BIOS support this feature.
904	  Otherwise the 8254 will be used for timing services.
905
906	  Choose N to continue using the legacy 8254 timer.
907
908config HPET_EMULATE_RTC
909	def_bool y
910	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
911
912# Mark as expert because too many people got it wrong.
913# The code disables itself when not needed.
914config DMI
915	default y
916	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
917	bool "Enable DMI scanning" if EXPERT
918	help
919	  Enabled scanning of DMI to identify machine quirks. Say Y
920	  here unless you have verified that your setup is not
921	  affected by entries in the DMI blacklist. Required by PNP
922	  BIOS code.
923
924config GART_IOMMU
925	bool "Old AMD GART IOMMU support"
926	select IOMMU_HELPER
927	select SWIOTLB
928	depends on X86_64 && PCI && AMD_NB
929	help
930	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
931	  GART based hardware IOMMUs.
932
933	  The GART supports full DMA access for devices with 32-bit access
934	  limitations, on systems with more than 3 GB. This is usually needed
935	  for USB, sound, many IDE/SATA chipsets and some other devices.
936
937	  Newer systems typically have a modern AMD IOMMU, supported via
938	  the CONFIG_AMD_IOMMU=y config option.
939
940	  In normal configurations this driver is only active when needed:
941	  there's more than 3 GB of memory and the system contains a
942	  32-bit limited device.
943
944	  If unsure, say Y.
945
946config BOOT_VESA_SUPPORT
947	bool
948	help
949	  If true, at least one selected framebuffer driver can take advantage
950	  of VESA video modes set at an early boot stage via the vga= parameter.
951
952config MAXSMP
953	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
954	depends on X86_64 && SMP && DEBUG_KERNEL
955	select CPUMASK_OFFSTACK
956	help
957	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
958	  If unsure, say N.
959
960#
961# The maximum number of CPUs supported:
962#
963# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
964# and which can be configured interactively in the
965# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
966#
967# The ranges are different on 32-bit and 64-bit kernels, depending on
968# hardware capabilities and scalability features of the kernel.
969#
970# ( If MAXSMP is enabled we just use the highest possible value and disable
971#   interactive configuration. )
972#
973
974config NR_CPUS_RANGE_BEGIN
975	int
976	default NR_CPUS_RANGE_END if MAXSMP
977	default    1 if !SMP
978	default    2
979
980config NR_CPUS_RANGE_END
981	int
982	depends on X86_32
983	default    8 if  SMP
984	default    1 if !SMP
985
986config NR_CPUS_RANGE_END
987	int
988	depends on X86_64
989	default 8192 if  SMP && CPUMASK_OFFSTACK
990	default  512 if  SMP && !CPUMASK_OFFSTACK
991	default    1 if !SMP
992
993config NR_CPUS_DEFAULT
994	int
995	depends on X86_32
996	default    8 if  SMP
997	default    1 if !SMP
998
999config NR_CPUS_DEFAULT
1000	int
1001	depends on X86_64
1002	default 8192 if  MAXSMP
1003	default   64 if  SMP
1004	default    1 if !SMP
1005
1006config NR_CPUS
1007	int "Maximum number of CPUs" if SMP && !MAXSMP
1008	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1009	default NR_CPUS_DEFAULT
1010	help
1011	  This allows you to specify the maximum number of CPUs which this
1012	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1013	  supported value is 8192, otherwise the maximum value is 512.  The
1014	  minimum value which makes sense is 2.
1015
1016	  This is purely to save memory: each supported CPU adds about 8KB
1017	  to the kernel image.
1018
1019config SCHED_CLUSTER
1020	bool "Cluster scheduler support"
1021	depends on SMP
1022	default y
1023	help
1024	  Cluster scheduler support improves the CPU scheduler's decision
1025	  making when dealing with machines that have clusters of CPUs.
1026	  Cluster usually means a couple of CPUs which are placed closely
1027	  by sharing mid-level caches, last-level cache tags or internal
1028	  busses.
1029
1030config SCHED_SMT
1031	def_bool y if SMP
1032
1033config SCHED_MC
1034	def_bool y
1035	prompt "Multi-core scheduler support"
1036	depends on SMP
1037	help
1038	  Multi-core scheduler support improves the CPU scheduler's decision
1039	  making when dealing with multi-core CPU chips at a cost of slightly
1040	  increased overhead in some places. If unsure say N here.
1041
1042config SCHED_MC_PRIO
1043	bool "CPU core priorities scheduler support"
1044	depends on SCHED_MC
1045	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1046	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1047	select CPU_FREQ
1048	default y
1049	help
1050	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1051	  core ordering determined at manufacturing time, which allows
1052	  certain cores to reach higher turbo frequencies (when running
1053	  single threaded workloads) than others.
1054
1055	  Enabling this kernel feature teaches the scheduler about
1056	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1057	  scheduler's CPU selection logic accordingly, so that higher
1058	  overall system performance can be achieved.
1059
1060	  This feature will have no effect on CPUs without this feature.
1061
1062	  If unsure say Y here.
1063
1064config UP_LATE_INIT
1065	def_bool y
1066	depends on !SMP && X86_LOCAL_APIC
1067
1068config X86_UP_APIC
1069	bool "Local APIC support on uniprocessors" if !PCI_MSI
1070	default PCI_MSI
1071	depends on X86_32 && !SMP
1072	help
1073	  A local APIC (Advanced Programmable Interrupt Controller) is an
1074	  integrated interrupt controller in the CPU. If you have a single-CPU
1075	  system which has a processor with a local APIC, you can say Y here to
1076	  enable and use it. If you say Y here even though your machine doesn't
1077	  have a local APIC, then the kernel will still run with no slowdown at
1078	  all. The local APIC supports CPU-generated self-interrupts (timer,
1079	  performance counters), and the NMI watchdog which detects hard
1080	  lockups.
1081
1082config X86_UP_IOAPIC
1083	bool "IO-APIC support on uniprocessors"
1084	depends on X86_UP_APIC
1085	help
1086	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1087	  SMP-capable replacement for PC-style interrupt controllers. Most
1088	  SMP systems and many recent uniprocessor systems have one.
1089
1090	  If you have a single-CPU system with an IO-APIC, you can say Y here
1091	  to use it. If you say Y here even though your machine doesn't have
1092	  an IO-APIC, then the kernel will still run with no slowdown at all.
1093
1094config X86_LOCAL_APIC
1095	def_bool y
1096	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1097	select IRQ_DOMAIN_HIERARCHY
1098
1099config ACPI_MADT_WAKEUP
1100	def_bool y
1101	depends on X86_64
1102	depends on ACPI
1103	depends on SMP
1104	depends on X86_LOCAL_APIC
1105
1106config X86_IO_APIC
1107	def_bool y
1108	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1109
1110config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1111	bool "Reroute for broken boot IRQs"
1112	depends on X86_IO_APIC
1113	help
1114	  This option enables a workaround that fixes a source of
1115	  spurious interrupts. This is recommended when threaded
1116	  interrupt handling is used on systems where the generation of
1117	  superfluous "boot interrupts" cannot be disabled.
1118
1119	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1120	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1121	  kernel does during interrupt handling). On chipsets where this
1122	  boot IRQ generation cannot be disabled, this workaround keeps
1123	  the original IRQ line masked so that only the equivalent "boot
1124	  IRQ" is delivered to the CPUs. The workaround also tells the
1125	  kernel to set up the IRQ handler on the boot IRQ line. In this
1126	  way only one interrupt is delivered to the kernel. Otherwise
1127	  the spurious second interrupt may cause the kernel to bring
1128	  down (vital) interrupt lines.
1129
1130	  Only affects "broken" chipsets. Interrupt sharing may be
1131	  increased on these systems.
1132
1133config X86_MCE
1134	bool "Machine Check / overheating reporting"
1135	select GENERIC_ALLOCATOR
1136	default y
1137	help
1138	  Machine Check support allows the processor to notify the
1139	  kernel if it detects a problem (e.g. overheating, data corruption).
1140	  The action the kernel takes depends on the severity of the problem,
1141	  ranging from warning messages to halting the machine.
1142
1143config X86_MCELOG_LEGACY
1144	bool "Support for deprecated /dev/mcelog character device"
1145	depends on X86_MCE
1146	help
1147	  Enable support for /dev/mcelog which is needed by the old mcelog
1148	  userspace logging daemon. Consider switching to the new generation
1149	  rasdaemon solution.
1150
1151config X86_MCE_INTEL
1152	def_bool y
1153	prompt "Intel MCE features"
1154	depends on X86_MCE && X86_LOCAL_APIC
1155	help
1156	  Additional support for intel specific MCE features such as
1157	  the thermal monitor.
1158
1159config X86_MCE_AMD
1160	def_bool y
1161	prompt "AMD MCE features"
1162	depends on X86_MCE && X86_LOCAL_APIC
1163	help
1164	  Additional support for AMD specific MCE features such as
1165	  the DRAM Error Threshold.
1166
1167config X86_ANCIENT_MCE
1168	bool "Support for old Pentium 5 / WinChip machine checks"
1169	depends on X86_32 && X86_MCE
1170	help
1171	  Include support for machine check handling on old Pentium 5 or WinChip
1172	  systems. These typically need to be enabled explicitly on the command
1173	  line.
1174
1175config X86_MCE_THRESHOLD
1176	depends on X86_MCE_AMD || X86_MCE_INTEL
1177	def_bool y
1178
1179config X86_MCE_INJECT
1180	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1181	tristate "Machine check injector support"
1182	help
1183	  Provide support for injecting machine checks for testing purposes.
1184	  If you don't know what a machine check is and you don't do kernel
1185	  QA it is safe to say n.
1186
1187source "arch/x86/events/Kconfig"
1188
1189config X86_LEGACY_VM86
1190	bool "Legacy VM86 support"
1191	depends on X86_32
1192	help
1193	  This option allows user programs to put the CPU into V8086
1194	  mode, which is an 80286-era approximation of 16-bit real mode.
1195
1196	  Some very old versions of X and/or vbetool require this option
1197	  for user mode setting.  Similarly, DOSEMU will use it if
1198	  available to accelerate real mode DOS programs.  However, any
1199	  recent version of DOSEMU, X, or vbetool should be fully
1200	  functional even without kernel VM86 support, as they will all
1201	  fall back to software emulation. Nevertheless, if you are using
1202	  a 16-bit DOS program where 16-bit performance matters, vm86
1203	  mode might be faster than emulation and you might want to
1204	  enable this option.
1205
1206	  Note that any app that works on a 64-bit kernel is unlikely to
1207	  need this option, as 64-bit kernels don't, and can't, support
1208	  V8086 mode. This option is also unrelated to 16-bit protected
1209	  mode and is not needed to run most 16-bit programs under Wine.
1210
1211	  Enabling this option increases the complexity of the kernel
1212	  and slows down exception handling a tiny bit.
1213
1214	  If unsure, say N here.
1215
1216config VM86
1217	bool
1218	default X86_LEGACY_VM86
1219
1220config X86_16BIT
1221	bool "Enable support for 16-bit segments" if EXPERT
1222	default y
1223	depends on MODIFY_LDT_SYSCALL
1224	help
1225	  This option is required by programs like Wine to run 16-bit
1226	  protected mode legacy code on x86 processors.  Disabling
1227	  this option saves about 300 bytes on i386, or around 6K text
1228	  plus 16K runtime memory on x86-64,
1229
1230config X86_ESPFIX32
1231	def_bool y
1232	depends on X86_16BIT && X86_32
1233
1234config X86_ESPFIX64
1235	def_bool y
1236	depends on X86_16BIT && X86_64
1237
1238config X86_VSYSCALL_EMULATION
1239	bool "Enable vsyscall emulation" if EXPERT
1240	default y
1241	depends on X86_64
1242	help
1243	  This enables emulation of the legacy vsyscall page.  Disabling
1244	  it is roughly equivalent to booting with vsyscall=none, except
1245	  that it will also disable the helpful warning if a program
1246	  tries to use a vsyscall.  With this option set to N, offending
1247	  programs will just segfault, citing addresses of the form
1248	  0xffffffffff600?00.
1249
1250	  This option is required by many programs built before 2013, and
1251	  care should be used even with newer programs if set to N.
1252
1253	  Disabling this option saves about 7K of kernel size and
1254	  possibly 4K of additional runtime pagetable memory.
1255
1256config X86_IOPL_IOPERM
1257	bool "IOPERM and IOPL Emulation"
1258	default y
1259	help
1260	  This enables the ioperm() and iopl() syscalls which are necessary
1261	  for legacy applications.
1262
1263	  Legacy IOPL support is an overbroad mechanism which allows user
1264	  space aside of accessing all 65536 I/O ports also to disable
1265	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1266	  capabilities and permission from potentially active security
1267	  modules.
1268
1269	  The emulation restricts the functionality of the syscall to
1270	  only allowing the full range I/O port access, but prevents the
1271	  ability to disable interrupts from user space which would be
1272	  granted if the hardware IOPL mechanism would be used.
1273
1274config TOSHIBA
1275	tristate "Toshiba Laptop support"
1276	depends on X86_32
1277	help
1278	  This adds a driver to safely access the System Management Mode of
1279	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1280	  not work on models with a Phoenix BIOS. The System Management Mode
1281	  is used to set the BIOS and power saving options on Toshiba portables.
1282
1283	  For information on utilities to make use of this driver see the
1284	  Toshiba Linux utilities web site at:
1285	  <http://www.buzzard.org.uk/toshiba/>.
1286
1287	  Say Y if you intend to run this kernel on a Toshiba portable.
1288	  Say N otherwise.
1289
1290config X86_REBOOTFIXUPS
1291	bool "Enable X86 board specific fixups for reboot"
1292	depends on X86_32
1293	help
1294	  This enables chipset and/or board specific fixups to be done
1295	  in order to get reboot to work correctly. This is only needed on
1296	  some combinations of hardware and BIOS. The symptom, for which
1297	  this config is intended, is when reboot ends with a stalled/hung
1298	  system.
1299
1300	  Currently, the only fixup is for the Geode machines using
1301	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1302
1303	  Say Y if you want to enable the fixup. Currently, it's safe to
1304	  enable this option even if you don't need it.
1305	  Say N otherwise.
1306
1307config MICROCODE
1308	def_bool y
1309	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1310	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1311
1312config MICROCODE_INITRD32
1313	def_bool y
1314	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1315
1316config MICROCODE_LATE_LOADING
1317	bool "Late microcode loading (DANGEROUS)"
1318	default n
1319	depends on MICROCODE && SMP
1320	help
1321	  Loading microcode late, when the system is up and executing instructions
1322	  is a tricky business and should be avoided if possible. Just the sequence
1323	  of synchronizing all cores and SMT threads is one fragile dance which does
1324	  not guarantee that cores might not softlock after the loading. Therefore,
1325	  use this at your own risk. Late loading taints the kernel unless the
1326	  microcode header indicates that it is safe for late loading via the
1327	  minimal revision check. This minimal revision check can be enforced on
1328	  the kernel command line with "microcode.minrev=Y".
1329
1330config MICROCODE_LATE_FORCE_MINREV
1331	bool "Enforce late microcode loading minimal revision check"
1332	default n
1333	depends on MICROCODE_LATE_LOADING
1334	help
1335	  To prevent that users load microcode late which modifies already
1336	  in use features, newer microcode patches have a minimum revision field
1337	  in the microcode header, which tells the kernel which minimum
1338	  revision must be active in the CPU to safely load that new microcode
1339	  late into the running system. If disabled the check will not
1340	  be enforced but the kernel will be tainted when the minimal
1341	  revision check fails.
1342
1343	  This minimal revision check can also be controlled via the
1344	  "microcode.minrev" parameter on the kernel command line.
1345
1346	  If unsure say Y.
1347
1348config X86_MSR
1349	tristate "/dev/cpu/*/msr - Model-specific register support"
1350	help
1351	  This device gives privileged processes access to the x86
1352	  Model-Specific Registers (MSRs).  It is a character device with
1353	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1354	  MSR accesses are directed to a specific CPU on multi-processor
1355	  systems.
1356
1357config X86_CPUID
1358	tristate "/dev/cpu/*/cpuid - CPU information support"
1359	help
1360	  This device gives processes access to the x86 CPUID instruction to
1361	  be executed on a specific processor.  It is a character device
1362	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1363	  /dev/cpu/31/cpuid.
1364
1365config HIGHMEM4G
1366	bool "High Memory Support"
1367	depends on X86_32
1368	help
1369	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1370	  However, the address space of 32-bit x86 processors is only 4
1371	  Gigabytes large. That means that, if you have a large amount of
1372	  physical memory, not all of it can be "permanently mapped" by the
1373	  kernel. The physical memory that's not permanently mapped is called
1374	  "high memory".
1375
1376	  If you are compiling a kernel which will never run on a machine with
1377	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1378	  choice and suitable for most users). This will result in a "3GB/1GB"
1379	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1380	  space and the remaining part of the 4GB virtual memory space is used
1381	  by the kernel to permanently map as much physical memory as
1382	  possible.
1383
1384	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1385	  answer "Y" here.
1386
1387	  If unsure, say N.
1388
1389choice
1390	prompt "Memory split" if EXPERT
1391	default VMSPLIT_3G
1392	depends on X86_32
1393	help
1394	  Select the desired split between kernel and user memory.
1395
1396	  If the address range available to the kernel is less than the
1397	  physical memory installed, the remaining memory will be available
1398	  as "high memory". Accessing high memory is a little more costly
1399	  than low memory, as it needs to be mapped into the kernel first.
1400	  Note that increasing the kernel address space limits the range
1401	  available to user programs, making the address space there
1402	  tighter.  Selecting anything other than the default 3G/1G split
1403	  will also likely make your kernel incompatible with binary-only
1404	  kernel modules.
1405
1406	  If you are not absolutely sure what you are doing, leave this
1407	  option alone!
1408
1409	config VMSPLIT_3G
1410		bool "3G/1G user/kernel split"
1411	config VMSPLIT_3G_OPT
1412		depends on !X86_PAE
1413		bool "3G/1G user/kernel split (for full 1G low memory)"
1414	config VMSPLIT_2G
1415		bool "2G/2G user/kernel split"
1416	config VMSPLIT_2G_OPT
1417		depends on !X86_PAE
1418		bool "2G/2G user/kernel split (for full 2G low memory)"
1419	config VMSPLIT_1G
1420		bool "1G/3G user/kernel split"
1421endchoice
1422
1423config PAGE_OFFSET
1424	hex
1425	default 0xB0000000 if VMSPLIT_3G_OPT
1426	default 0x80000000 if VMSPLIT_2G
1427	default 0x78000000 if VMSPLIT_2G_OPT
1428	default 0x40000000 if VMSPLIT_1G
1429	default 0xC0000000
1430	depends on X86_32
1431
1432config HIGHMEM
1433	def_bool HIGHMEM4G
1434
1435config X86_PAE
1436	bool "PAE (Physical Address Extension) Support"
1437	depends on X86_32 && X86_HAVE_PAE
1438	select PHYS_ADDR_T_64BIT
1439	help
1440	  PAE is required for NX support, and furthermore enables
1441	  larger swapspace support for non-overcommit purposes. It
1442	  has the cost of more pagetable lookup overhead, and also
1443	  consumes more pagetable space per process.
1444
1445config X86_5LEVEL
1446	bool "Enable 5-level page tables support"
1447	default y
1448	select DYNAMIC_MEMORY_LAYOUT
1449	select SPARSEMEM_VMEMMAP
1450	depends on X86_64
1451	help
1452	  5-level paging enables access to larger address space:
1453	  up to 128 PiB of virtual address space and 4 PiB of
1454	  physical address space.
1455
1456	  It will be supported by future Intel CPUs.
1457
1458	  A kernel with the option enabled can be booted on machines that
1459	  support 4- or 5-level paging.
1460
1461	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1462	  information.
1463
1464	  Say N if unsure.
1465
1466config X86_DIRECT_GBPAGES
1467	def_bool y
1468	depends on X86_64
1469	help
1470	  Certain kernel features effectively disable kernel
1471	  linear 1 GB mappings (even if the CPU otherwise
1472	  supports them), so don't confuse the user by printing
1473	  that we have them enabled.
1474
1475config X86_CPA_STATISTICS
1476	bool "Enable statistic for Change Page Attribute"
1477	depends on DEBUG_FS
1478	help
1479	  Expose statistics about the Change Page Attribute mechanism, which
1480	  helps to determine the effectiveness of preserving large and huge
1481	  page mappings when mapping protections are changed.
1482
1483config X86_MEM_ENCRYPT
1484	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1485	select DYNAMIC_PHYSICAL_MASK
1486	def_bool n
1487
1488config AMD_MEM_ENCRYPT
1489	bool "AMD Secure Memory Encryption (SME) support"
1490	depends on X86_64 && CPU_SUP_AMD
1491	depends on EFI_STUB
1492	select DMA_COHERENT_POOL
1493	select ARCH_USE_MEMREMAP_PROT
1494	select INSTRUCTION_DECODER
1495	select ARCH_HAS_CC_PLATFORM
1496	select X86_MEM_ENCRYPT
1497	select UNACCEPTED_MEMORY
1498	select CRYPTO_LIB_AESGCM
1499	help
1500	  Say yes to enable support for the encryption of system memory.
1501	  This requires an AMD processor that supports Secure Memory
1502	  Encryption (SME).
1503
1504# Common NUMA Features
1505config NUMA
1506	bool "NUMA Memory Allocation and Scheduler Support"
1507	depends on SMP
1508	depends on X86_64
1509	select USE_PERCPU_NUMA_NODE_ID
1510	select OF_NUMA if OF
1511	help
1512	  Enable NUMA (Non-Uniform Memory Access) support.
1513
1514	  The kernel will try to allocate memory used by a CPU on the
1515	  local memory controller of the CPU and add some more
1516	  NUMA awareness to the kernel.
1517
1518	  For 64-bit this is recommended if the system is Intel Core i7
1519	  (or later), AMD Opteron, or EM64T NUMA.
1520
1521	  Otherwise, you should say N.
1522
1523config AMD_NUMA
1524	def_bool y
1525	prompt "Old style AMD Opteron NUMA detection"
1526	depends on X86_64 && NUMA && PCI
1527	help
1528	  Enable AMD NUMA node topology detection.  You should say Y here if
1529	  you have a multi processor AMD system. This uses an old method to
1530	  read the NUMA configuration directly from the builtin Northbridge
1531	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1532	  which also takes priority if both are compiled in.
1533
1534config X86_64_ACPI_NUMA
1535	def_bool y
1536	prompt "ACPI NUMA detection"
1537	depends on X86_64 && NUMA && ACPI && PCI
1538	select ACPI_NUMA
1539	help
1540	  Enable ACPI SRAT based node topology detection.
1541
1542config NODES_SHIFT
1543	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1544	range 1 10
1545	default "10" if MAXSMP
1546	default "6" if X86_64
1547	default "3"
1548	depends on NUMA
1549	help
1550	  Specify the maximum number of NUMA Nodes available on the target
1551	  system.  Increases memory reserved to accommodate various tables.
1552
1553config ARCH_FLATMEM_ENABLE
1554	def_bool y
1555	depends on X86_32 && !NUMA
1556
1557config ARCH_SPARSEMEM_ENABLE
1558	def_bool y
1559	depends on X86_64 || NUMA || X86_32
1560	select SPARSEMEM_STATIC if X86_32
1561	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1562
1563config ARCH_SPARSEMEM_DEFAULT
1564	def_bool X86_64 || (NUMA && X86_32)
1565
1566config ARCH_SELECT_MEMORY_MODEL
1567	def_bool y
1568	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1569
1570config ARCH_MEMORY_PROBE
1571	bool "Enable sysfs memory/probe interface"
1572	depends on MEMORY_HOTPLUG
1573	help
1574	  This option enables a sysfs memory/probe interface for testing.
1575	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1576	  If you are unsure how to answer this question, answer N.
1577
1578config ARCH_PROC_KCORE_TEXT
1579	def_bool y
1580	depends on X86_64 && PROC_KCORE
1581
1582config ILLEGAL_POINTER_VALUE
1583	hex
1584	default 0 if X86_32
1585	default 0xdead000000000000 if X86_64
1586
1587config X86_PMEM_LEGACY_DEVICE
1588	bool
1589
1590config X86_PMEM_LEGACY
1591	tristate "Support non-standard NVDIMMs and ADR protected memory"
1592	depends on PHYS_ADDR_T_64BIT
1593	depends on BLK_DEV
1594	select X86_PMEM_LEGACY_DEVICE
1595	select NUMA_KEEP_MEMINFO if NUMA
1596	select LIBNVDIMM
1597	help
1598	  Treat memory marked using the non-standard e820 type of 12 as used
1599	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1600	  The kernel will offer these regions to the 'pmem' driver so
1601	  they can be used for persistent storage.
1602
1603	  Say Y if unsure.
1604
1605config X86_CHECK_BIOS_CORRUPTION
1606	bool "Check for low memory corruption"
1607	help
1608	  Periodically check for memory corruption in low memory, which
1609	  is suspected to be caused by BIOS.  Even when enabled in the
1610	  configuration, it is disabled at runtime.  Enable it by
1611	  setting "memory_corruption_check=1" on the kernel command
1612	  line.  By default it scans the low 64k of memory every 60
1613	  seconds; see the memory_corruption_check_size and
1614	  memory_corruption_check_period parameters in
1615	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1616
1617	  When enabled with the default parameters, this option has
1618	  almost no overhead, as it reserves a relatively small amount
1619	  of memory and scans it infrequently.  It both detects corruption
1620	  and prevents it from affecting the running system.
1621
1622	  It is, however, intended as a diagnostic tool; if repeatable
1623	  BIOS-originated corruption always affects the same memory,
1624	  you can use memmap= to prevent the kernel from using that
1625	  memory.
1626
1627config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1628	bool "Set the default setting of memory_corruption_check"
1629	depends on X86_CHECK_BIOS_CORRUPTION
1630	default y
1631	help
1632	  Set whether the default state of memory_corruption_check is
1633	  on or off.
1634
1635config MATH_EMULATION
1636	bool
1637	depends on MODIFY_LDT_SYSCALL
1638	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1639	help
1640	  Linux can emulate a math coprocessor (used for floating point
1641	  operations) if you don't have one. 486DX and Pentium processors have
1642	  a math coprocessor built in, 486SX and 386 do not, unless you added
1643	  a 487DX or 387, respectively. (The messages during boot time can
1644	  give you some hints here ["man dmesg"].) Everyone needs either a
1645	  coprocessor or this emulation.
1646
1647	  If you don't have a math coprocessor, you need to say Y here; if you
1648	  say Y here even though you have a coprocessor, the coprocessor will
1649	  be used nevertheless. (This behavior can be changed with the kernel
1650	  command line option "no387", which comes handy if your coprocessor
1651	  is broken. Try "man bootparam" or see the documentation of your boot
1652	  loader (lilo or loadlin) about how to pass options to the kernel at
1653	  boot time.) This means that it is a good idea to say Y here if you
1654	  intend to use this kernel on different machines.
1655
1656	  More information about the internals of the Linux math coprocessor
1657	  emulation can be found in <file:arch/x86/math-emu/README>.
1658
1659	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1660	  kernel, it won't hurt.
1661
1662config MTRR
1663	def_bool y
1664	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1665	help
1666	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1667	  the Memory Type Range Registers (MTRRs) may be used to control
1668	  processor access to memory ranges. This is most useful if you have
1669	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1670	  allows bus write transfers to be combined into a larger transfer
1671	  before bursting over the PCI/AGP bus. This can increase performance
1672	  of image write operations 2.5 times or more. Saying Y here creates a
1673	  /proc/mtrr file which may be used to manipulate your processor's
1674	  MTRRs. Typically the X server should use this.
1675
1676	  This code has a reasonably generic interface so that similar
1677	  control registers on other processors can be easily supported
1678	  as well:
1679
1680	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1681	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1682	  these, the ARRs are used to emulate the MTRRs.
1683	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1684	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1685	  write-combining. All of these processors are supported by this code
1686	  and it makes sense to say Y here if you have one of them.
1687
1688	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1689	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1690	  can lead to all sorts of problems, so it's good to say Y here.
1691
1692	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1693	  just add about 9 KB to your kernel.
1694
1695	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1696
1697config MTRR_SANITIZER
1698	def_bool y
1699	prompt "MTRR cleanup support"
1700	depends on MTRR
1701	help
1702	  Convert MTRR layout from continuous to discrete, so X drivers can
1703	  add writeback entries.
1704
1705	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1706	  The largest mtrr entry size for a continuous block can be set with
1707	  mtrr_chunk_size.
1708
1709	  If unsure, say Y.
1710
1711config MTRR_SANITIZER_ENABLE_DEFAULT
1712	int "MTRR cleanup enable value (0-1)"
1713	range 0 1
1714	default "0"
1715	depends on MTRR_SANITIZER
1716	help
1717	  Enable mtrr cleanup default value
1718
1719config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1720	int "MTRR cleanup spare reg num (0-7)"
1721	range 0 7
1722	default "1"
1723	depends on MTRR_SANITIZER
1724	help
1725	  mtrr cleanup spare entries default, it can be changed via
1726	  mtrr_spare_reg_nr=N on the kernel command line.
1727
1728config X86_PAT
1729	def_bool y
1730	prompt "x86 PAT support" if EXPERT
1731	depends on MTRR
1732	select ARCH_USES_PG_ARCH_2
1733	help
1734	  Use PAT attributes to setup page level cache control.
1735
1736	  PATs are the modern equivalents of MTRRs and are much more
1737	  flexible than MTRRs.
1738
1739	  Say N here if you see bootup problems (boot crash, boot hang,
1740	  spontaneous reboots) or a non-working video driver.
1741
1742	  If unsure, say Y.
1743
1744config X86_UMIP
1745	def_bool y
1746	prompt "User Mode Instruction Prevention" if EXPERT
1747	help
1748	  User Mode Instruction Prevention (UMIP) is a security feature in
1749	  some x86 processors. If enabled, a general protection fault is
1750	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1751	  executed in user mode. These instructions unnecessarily expose
1752	  information about the hardware state.
1753
1754	  The vast majority of applications do not use these instructions.
1755	  For the very few that do, software emulation is provided in
1756	  specific cases in protected and virtual-8086 modes. Emulated
1757	  results are dummy.
1758
1759config CC_HAS_IBT
1760	# GCC >= 9 and binutils >= 2.29
1761	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1762	# Clang/LLVM >= 14
1763	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1764	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1765	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1766		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1767		  $(as-instr,endbr64)
1768
1769config X86_CET
1770	def_bool n
1771	help
1772	  CET features configured (Shadow stack or IBT)
1773
1774config X86_KERNEL_IBT
1775	prompt "Indirect Branch Tracking"
1776	def_bool y
1777	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1778	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1779	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1780	select OBJTOOL
1781	select X86_CET
1782	help
1783	  Build the kernel with support for Indirect Branch Tracking, a
1784	  hardware support course-grain forward-edge Control Flow Integrity
1785	  protection. It enforces that all indirect calls must land on
1786	  an ENDBR instruction, as such, the compiler will instrument the
1787	  code with them to make this happen.
1788
1789	  In addition to building the kernel with IBT, seal all functions that
1790	  are not indirect call targets, avoiding them ever becoming one.
1791
1792	  This requires LTO like objtool runs and will slow down the build. It
1793	  does significantly reduce the number of ENDBR instructions in the
1794	  kernel image.
1795
1796config X86_INTEL_MEMORY_PROTECTION_KEYS
1797	prompt "Memory Protection Keys"
1798	def_bool y
1799	# Note: only available in 64-bit mode
1800	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1801	select ARCH_USES_HIGH_VMA_FLAGS
1802	select ARCH_HAS_PKEYS
1803	help
1804	  Memory Protection Keys provides a mechanism for enforcing
1805	  page-based protections, but without requiring modification of the
1806	  page tables when an application changes protection domains.
1807
1808	  For details, see Documentation/core-api/protection-keys.rst
1809
1810	  If unsure, say y.
1811
1812config ARCH_PKEY_BITS
1813	int
1814	default 4
1815
1816choice
1817	prompt "TSX enable mode"
1818	depends on CPU_SUP_INTEL
1819	default X86_INTEL_TSX_MODE_OFF
1820	help
1821	  Intel's TSX (Transactional Synchronization Extensions) feature
1822	  allows to optimize locking protocols through lock elision which
1823	  can lead to a noticeable performance boost.
1824
1825	  On the other hand it has been shown that TSX can be exploited
1826	  to form side channel attacks (e.g. TAA) and chances are there
1827	  will be more of those attacks discovered in the future.
1828
1829	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1830	  might override this decision by tsx=on the command line parameter.
1831	  Even with TSX enabled, the kernel will attempt to enable the best
1832	  possible TAA mitigation setting depending on the microcode available
1833	  for the particular machine.
1834
1835	  This option allows to set the default tsx mode between tsx=on, =off
1836	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1837	  details.
1838
1839	  Say off if not sure, auto if TSX is in use but it should be used on safe
1840	  platforms or on if TSX is in use and the security aspect of tsx is not
1841	  relevant.
1842
1843config X86_INTEL_TSX_MODE_OFF
1844	bool "off"
1845	help
1846	  TSX is disabled if possible - equals to tsx=off command line parameter.
1847
1848config X86_INTEL_TSX_MODE_ON
1849	bool "on"
1850	help
1851	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1852	  line parameter.
1853
1854config X86_INTEL_TSX_MODE_AUTO
1855	bool "auto"
1856	help
1857	  TSX is enabled on TSX capable HW that is believed to be safe against
1858	  side channel attacks- equals the tsx=auto command line parameter.
1859endchoice
1860
1861config X86_SGX
1862	bool "Software Guard eXtensions (SGX)"
1863	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1864	depends on CRYPTO=y
1865	depends on CRYPTO_SHA256=y
1866	select MMU_NOTIFIER
1867	select NUMA_KEEP_MEMINFO if NUMA
1868	select XARRAY_MULTI
1869	help
1870	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1871	  that can be used by applications to set aside private regions of code
1872	  and data, referred to as enclaves. An enclave's private memory can
1873	  only be accessed by code running within the enclave. Accesses from
1874	  outside the enclave, including other enclaves, are disallowed by
1875	  hardware.
1876
1877	  If unsure, say N.
1878
1879config X86_USER_SHADOW_STACK
1880	bool "X86 userspace shadow stack"
1881	depends on AS_WRUSS
1882	depends on X86_64
1883	select ARCH_USES_HIGH_VMA_FLAGS
1884	select ARCH_HAS_USER_SHADOW_STACK
1885	select X86_CET
1886	help
1887	  Shadow stack protection is a hardware feature that detects function
1888	  return address corruption.  This helps mitigate ROP attacks.
1889	  Applications must be enabled to use it, and old userspace does not
1890	  get protection "for free".
1891
1892	  CPUs supporting shadow stacks were first released in 2020.
1893
1894	  See Documentation/arch/x86/shstk.rst for more information.
1895
1896	  If unsure, say N.
1897
1898config INTEL_TDX_HOST
1899	bool "Intel Trust Domain Extensions (TDX) host support"
1900	depends on CPU_SUP_INTEL
1901	depends on X86_64
1902	depends on KVM_INTEL
1903	depends on X86_X2APIC
1904	select ARCH_KEEP_MEMBLOCK
1905	depends on CONTIG_ALLOC
1906	depends on !KEXEC_CORE
1907	depends on X86_MCE
1908	help
1909	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1910	  host and certain physical attacks.  This option enables necessary TDX
1911	  support in the host kernel to run confidential VMs.
1912
1913	  If unsure, say N.
1914
1915config EFI
1916	bool "EFI runtime service support"
1917	depends on ACPI
1918	select UCS2_STRING
1919	select EFI_RUNTIME_WRAPPERS
1920	select ARCH_USE_MEMREMAP_PROT
1921	select EFI_RUNTIME_MAP if KEXEC_CORE
1922	help
1923	  This enables the kernel to use EFI runtime services that are
1924	  available (such as the EFI variable services).
1925
1926	  This option is only useful on systems that have EFI firmware.
1927	  In addition, you should use the latest ELILO loader available
1928	  at <http://elilo.sourceforge.net> in order to take advantage
1929	  of EFI runtime services. However, even with this option, the
1930	  resultant kernel should continue to boot on existing non-EFI
1931	  platforms.
1932
1933config EFI_STUB
1934	bool "EFI stub support"
1935	depends on EFI
1936	select RELOCATABLE
1937	help
1938	  This kernel feature allows a bzImage to be loaded directly
1939	  by EFI firmware without the use of a bootloader.
1940
1941	  See Documentation/admin-guide/efi-stub.rst for more information.
1942
1943config EFI_HANDOVER_PROTOCOL
1944	bool "EFI handover protocol (DEPRECATED)"
1945	depends on EFI_STUB
1946	default y
1947	help
1948	  Select this in order to include support for the deprecated EFI
1949	  handover protocol, which defines alternative entry points into the
1950	  EFI stub.  This is a practice that has no basis in the UEFI
1951	  specification, and requires a priori knowledge on the part of the
1952	  bootloader about Linux/x86 specific ways of passing the command line
1953	  and initrd, and where in memory those assets may be loaded.
1954
1955	  If in doubt, say Y. Even though the corresponding support is not
1956	  present in upstream GRUB or other bootloaders, most distros build
1957	  GRUB with numerous downstream patches applied, and may rely on the
1958	  handover protocol as as result.
1959
1960config EFI_MIXED
1961	bool "EFI mixed-mode support"
1962	depends on EFI_STUB && X86_64
1963	help
1964	  Enabling this feature allows a 64-bit kernel to be booted
1965	  on a 32-bit firmware, provided that your CPU supports 64-bit
1966	  mode.
1967
1968	  Note that it is not possible to boot a mixed-mode enabled
1969	  kernel via the EFI boot stub - a bootloader that supports
1970	  the EFI handover protocol must be used.
1971
1972	  If unsure, say N.
1973
1974config EFI_RUNTIME_MAP
1975	bool "Export EFI runtime maps to sysfs" if EXPERT
1976	depends on EFI
1977	help
1978	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1979	  That memory map is required by the 2nd kernel to set up EFI virtual
1980	  mappings after kexec, but can also be used for debugging purposes.
1981
1982	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1983
1984source "kernel/Kconfig.hz"
1985
1986config ARCH_SUPPORTS_KEXEC
1987	def_bool y
1988
1989config ARCH_SUPPORTS_KEXEC_FILE
1990	def_bool X86_64
1991
1992config ARCH_SELECTS_KEXEC_FILE
1993	def_bool y
1994	depends on KEXEC_FILE
1995	select HAVE_IMA_KEXEC if IMA
1996
1997config ARCH_SUPPORTS_KEXEC_PURGATORY
1998	def_bool y
1999
2000config ARCH_SUPPORTS_KEXEC_SIG
2001	def_bool y
2002
2003config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2004	def_bool y
2005
2006config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2007	def_bool y
2008
2009config ARCH_SUPPORTS_KEXEC_JUMP
2010	def_bool y
2011
2012config ARCH_SUPPORTS_CRASH_DUMP
2013	def_bool X86_64 || (X86_32 && HIGHMEM)
2014
2015config ARCH_DEFAULT_CRASH_DUMP
2016	def_bool y
2017
2018config ARCH_SUPPORTS_CRASH_HOTPLUG
2019	def_bool y
2020
2021config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2022	def_bool CRASH_RESERVE
2023
2024config PHYSICAL_START
2025	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2026	default "0x1000000"
2027	help
2028	  This gives the physical address where the kernel is loaded.
2029
2030	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2031	  will decompress itself to above physical address and run from there.
2032	  Otherwise, bzImage will run from the address where it has been loaded
2033	  by the boot loader. The only exception is if it is loaded below the
2034	  above physical address, in which case it will relocate itself there.
2035
2036	  In normal kdump cases one does not have to set/change this option
2037	  as now bzImage can be compiled as a completely relocatable image
2038	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2039	  address. This option is mainly useful for the folks who don't want
2040	  to use a bzImage for capturing the crash dump and want to use a
2041	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2042	  to be specifically compiled to run from a specific memory area
2043	  (normally a reserved region) and this option comes handy.
2044
2045	  So if you are using bzImage for capturing the crash dump,
2046	  leave the value here unchanged to 0x1000000 and set
2047	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2048	  for capturing the crash dump change this value to start of
2049	  the reserved region.  In other words, it can be set based on
2050	  the "X" value as specified in the "crashkernel=YM@XM"
2051	  command line boot parameter passed to the panic-ed
2052	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2053	  for more details about crash dumps.
2054
2055	  Usage of bzImage for capturing the crash dump is recommended as
2056	  one does not have to build two kernels. Same kernel can be used
2057	  as production kernel and capture kernel. Above option should have
2058	  gone away after relocatable bzImage support is introduced. But it
2059	  is present because there are users out there who continue to use
2060	  vmlinux for dump capture. This option should go away down the
2061	  line.
2062
2063	  Don't change this unless you know what you are doing.
2064
2065config RELOCATABLE
2066	bool "Build a relocatable kernel"
2067	default y
2068	help
2069	  This builds a kernel image that retains relocation information
2070	  so it can be loaded someplace besides the default 1MB.
2071	  The relocations tend to make the kernel binary about 10% larger,
2072	  but are discarded at runtime.
2073
2074	  One use is for the kexec on panic case where the recovery kernel
2075	  must live at a different physical address than the primary
2076	  kernel.
2077
2078	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2079	  it has been loaded at and the compile time physical address
2080	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2081
2082config RANDOMIZE_BASE
2083	bool "Randomize the address of the kernel image (KASLR)"
2084	depends on RELOCATABLE
2085	default y
2086	help
2087	  In support of Kernel Address Space Layout Randomization (KASLR),
2088	  this randomizes the physical address at which the kernel image
2089	  is decompressed and the virtual address where the kernel
2090	  image is mapped, as a security feature that deters exploit
2091	  attempts relying on knowledge of the location of kernel
2092	  code internals.
2093
2094	  On 64-bit, the kernel physical and virtual addresses are
2095	  randomized separately. The physical address will be anywhere
2096	  between 16MB and the top of physical memory (up to 64TB). The
2097	  virtual address will be randomized from 16MB up to 1GB (9 bits
2098	  of entropy). Note that this also reduces the memory space
2099	  available to kernel modules from 1.5GB to 1GB.
2100
2101	  On 32-bit, the kernel physical and virtual addresses are
2102	  randomized together. They will be randomized from 16MB up to
2103	  512MB (8 bits of entropy).
2104
2105	  Entropy is generated using the RDRAND instruction if it is
2106	  supported. If RDTSC is supported, its value is mixed into
2107	  the entropy pool as well. If neither RDRAND nor RDTSC are
2108	  supported, then entropy is read from the i8254 timer. The
2109	  usable entropy is limited by the kernel being built using
2110	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2111	  minimum of 2MB. As a result, only 10 bits of entropy are
2112	  theoretically possible, but the implementations are further
2113	  limited due to memory layouts.
2114
2115	  If unsure, say Y.
2116
2117# Relocation on x86 needs some additional build support
2118config X86_NEED_RELOCS
2119	def_bool y
2120	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2121
2122config PHYSICAL_ALIGN
2123	hex "Alignment value to which kernel should be aligned"
2124	default "0x200000"
2125	range 0x2000 0x1000000 if X86_32
2126	range 0x200000 0x1000000 if X86_64
2127	help
2128	  This value puts the alignment restrictions on physical address
2129	  where kernel is loaded and run from. Kernel is compiled for an
2130	  address which meets above alignment restriction.
2131
2132	  If bootloader loads the kernel at a non-aligned address and
2133	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2134	  address aligned to above value and run from there.
2135
2136	  If bootloader loads the kernel at a non-aligned address and
2137	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2138	  load address and decompress itself to the address it has been
2139	  compiled for and run from there. The address for which kernel is
2140	  compiled already meets above alignment restrictions. Hence the
2141	  end result is that kernel runs from a physical address meeting
2142	  above alignment restrictions.
2143
2144	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2145	  this value must be a multiple of 0x200000.
2146
2147	  Don't change this unless you know what you are doing.
2148
2149config DYNAMIC_MEMORY_LAYOUT
2150	bool
2151	help
2152	  This option makes base addresses of vmalloc and vmemmap as well as
2153	  __PAGE_OFFSET movable during boot.
2154
2155config RANDOMIZE_MEMORY
2156	bool "Randomize the kernel memory sections"
2157	depends on X86_64
2158	depends on RANDOMIZE_BASE
2159	select DYNAMIC_MEMORY_LAYOUT
2160	default RANDOMIZE_BASE
2161	help
2162	  Randomizes the base virtual address of kernel memory sections
2163	  (physical memory mapping, vmalloc & vmemmap). This security feature
2164	  makes exploits relying on predictable memory locations less reliable.
2165
2166	  The order of allocations remains unchanged. Entropy is generated in
2167	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2168	  configuration have in average 30,000 different possible virtual
2169	  addresses for each memory section.
2170
2171	  If unsure, say Y.
2172
2173config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2174	hex "Physical memory mapping padding" if EXPERT
2175	depends on RANDOMIZE_MEMORY
2176	default "0xa" if MEMORY_HOTPLUG
2177	default "0x0"
2178	range 0x1 0x40 if MEMORY_HOTPLUG
2179	range 0x0 0x40
2180	help
2181	  Define the padding in terabytes added to the existing physical
2182	  memory size during kernel memory randomization. It is useful
2183	  for memory hotplug support but reduces the entropy available for
2184	  address randomization.
2185
2186	  If unsure, leave at the default value.
2187
2188config ADDRESS_MASKING
2189	bool "Linear Address Masking support"
2190	depends on X86_64
2191	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2192	help
2193	  Linear Address Masking (LAM) modifies the checking that is applied
2194	  to 64-bit linear addresses, allowing software to use of the
2195	  untranslated address bits for metadata.
2196
2197	  The capability can be used for efficient address sanitizers (ASAN)
2198	  implementation and for optimizations in JITs.
2199
2200config HOTPLUG_CPU
2201	def_bool y
2202	depends on SMP
2203
2204config COMPAT_VDSO
2205	def_bool n
2206	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2207	depends on COMPAT_32
2208	help
2209	  Certain buggy versions of glibc will crash if they are
2210	  presented with a 32-bit vDSO that is not mapped at the address
2211	  indicated in its segment table.
2212
2213	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2214	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2215	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2216	  the only released version with the bug, but OpenSUSE 9
2217	  contains a buggy "glibc 2.3.2".
2218
2219	  The symptom of the bug is that everything crashes on startup, saying:
2220	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2221
2222	  Saying Y here changes the default value of the vdso32 boot
2223	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2224	  This works around the glibc bug but hurts performance.
2225
2226	  If unsure, say N: if you are compiling your own kernel, you
2227	  are unlikely to be using a buggy version of glibc.
2228
2229choice
2230	prompt "vsyscall table for legacy applications"
2231	depends on X86_64
2232	default LEGACY_VSYSCALL_XONLY
2233	help
2234	  Legacy user code that does not know how to find the vDSO expects
2235	  to be able to issue three syscalls by calling fixed addresses in
2236	  kernel space. Since this location is not randomized with ASLR,
2237	  it can be used to assist security vulnerability exploitation.
2238
2239	  This setting can be changed at boot time via the kernel command
2240	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2241	  is deprecated and can only be enabled using the kernel command
2242	  line.
2243
2244	  On a system with recent enough glibc (2.14 or newer) and no
2245	  static binaries, you can say None without a performance penalty
2246	  to improve security.
2247
2248	  If unsure, select "Emulate execution only".
2249
2250	config LEGACY_VSYSCALL_XONLY
2251		bool "Emulate execution only"
2252		help
2253		  The kernel traps and emulates calls into the fixed vsyscall
2254		  address mapping and does not allow reads.  This
2255		  configuration is recommended when userspace might use the
2256		  legacy vsyscall area but support for legacy binary
2257		  instrumentation of legacy code is not needed.  It mitigates
2258		  certain uses of the vsyscall area as an ASLR-bypassing
2259		  buffer.
2260
2261	config LEGACY_VSYSCALL_NONE
2262		bool "None"
2263		help
2264		  There will be no vsyscall mapping at all. This will
2265		  eliminate any risk of ASLR bypass due to the vsyscall
2266		  fixed address mapping. Attempts to use the vsyscalls
2267		  will be reported to dmesg, so that either old or
2268		  malicious userspace programs can be identified.
2269
2270endchoice
2271
2272config CMDLINE_BOOL
2273	bool "Built-in kernel command line"
2274	help
2275	  Allow for specifying boot arguments to the kernel at
2276	  build time.  On some systems (e.g. embedded ones), it is
2277	  necessary or convenient to provide some or all of the
2278	  kernel boot arguments with the kernel itself (that is,
2279	  to not rely on the boot loader to provide them.)
2280
2281	  To compile command line arguments into the kernel,
2282	  set this option to 'Y', then fill in the
2283	  boot arguments in CONFIG_CMDLINE.
2284
2285	  Systems with fully functional boot loaders (i.e. non-embedded)
2286	  should leave this option set to 'N'.
2287
2288config CMDLINE
2289	string "Built-in kernel command string"
2290	depends on CMDLINE_BOOL
2291	default ""
2292	help
2293	  Enter arguments here that should be compiled into the kernel
2294	  image and used at boot time.  If the boot loader provides a
2295	  command line at boot time, it is appended to this string to
2296	  form the full kernel command line, when the system boots.
2297
2298	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2299	  change this behavior.
2300
2301	  In most cases, the command line (whether built-in or provided
2302	  by the boot loader) should specify the device for the root
2303	  file system.
2304
2305config CMDLINE_OVERRIDE
2306	bool "Built-in command line overrides boot loader arguments"
2307	depends on CMDLINE_BOOL && CMDLINE != ""
2308	help
2309	  Set this option to 'Y' to have the kernel ignore the boot loader
2310	  command line, and use ONLY the built-in command line.
2311
2312	  This is used to work around broken boot loaders.  This should
2313	  be set to 'N' under normal conditions.
2314
2315config MODIFY_LDT_SYSCALL
2316	bool "Enable the LDT (local descriptor table)" if EXPERT
2317	default y
2318	help
2319	  Linux can allow user programs to install a per-process x86
2320	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2321	  call.  This is required to run 16-bit or segmented code such as
2322	  DOSEMU or some Wine programs.  It is also used by some very old
2323	  threading libraries.
2324
2325	  Enabling this feature adds a small amount of overhead to
2326	  context switches and increases the low-level kernel attack
2327	  surface.  Disabling it removes the modify_ldt(2) system call.
2328
2329	  Saying 'N' here may make sense for embedded or server kernels.
2330
2331config STRICT_SIGALTSTACK_SIZE
2332	bool "Enforce strict size checking for sigaltstack"
2333	depends on DYNAMIC_SIGFRAME
2334	help
2335	  For historical reasons MINSIGSTKSZ is a constant which became
2336	  already too small with AVX512 support. Add a mechanism to
2337	  enforce strict checking of the sigaltstack size against the
2338	  real size of the FPU frame. This option enables the check
2339	  by default. It can also be controlled via the kernel command
2340	  line option 'strict_sas_size' independent of this config
2341	  switch. Enabling it might break existing applications which
2342	  allocate a too small sigaltstack but 'work' because they
2343	  never get a signal delivered.
2344
2345	  Say 'N' unless you want to really enforce this check.
2346
2347config CFI_AUTO_DEFAULT
2348	bool "Attempt to use FineIBT by default at boot time"
2349	depends on FINEIBT
2350	default y
2351	help
2352	  Attempt to use FineIBT by default at boot time. If enabled,
2353	  this is the same as booting with "cfi=auto". If disabled,
2354	  this is the same as booting with "cfi=kcfi".
2355
2356source "kernel/livepatch/Kconfig"
2357
2358config X86_BUS_LOCK_DETECT
2359	bool "Split Lock Detect and Bus Lock Detect support"
2360	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2361	default y
2362	help
2363	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2364	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2365
2366endmenu
2367
2368config CC_HAS_NAMED_AS
2369	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2370	depends on CC_IS_GCC
2371
2372#
2373# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2374# are incompatible with named address spaces with GCC < 13.3
2375# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2376#
2377
2378config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2379	def_bool y
2380	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2381	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2382
2383config USE_X86_SEG_SUPPORT
2384	def_bool CC_HAS_NAMED_AS
2385	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2386
2387config CC_HAS_SLS
2388	def_bool $(cc-option,-mharden-sls=all)
2389
2390config CC_HAS_RETURN_THUNK
2391	def_bool $(cc-option,-mfunction-return=thunk-extern)
2392
2393config CC_HAS_ENTRY_PADDING
2394	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2395
2396config CC_HAS_KCFI_ARITY
2397	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2398	depends on CC_IS_CLANG && !RUST
2399
2400config FUNCTION_PADDING_CFI
2401	int
2402	default 59 if FUNCTION_ALIGNMENT_64B
2403	default 27 if FUNCTION_ALIGNMENT_32B
2404	default 11 if FUNCTION_ALIGNMENT_16B
2405	default  3 if FUNCTION_ALIGNMENT_8B
2406	default  0
2407
2408# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2409# except Kconfig can't do arithmetic :/
2410config FUNCTION_PADDING_BYTES
2411	int
2412	default FUNCTION_PADDING_CFI if CFI_CLANG
2413	default FUNCTION_ALIGNMENT
2414
2415config CALL_PADDING
2416	def_bool n
2417	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2418	select FUNCTION_ALIGNMENT_16B
2419
2420config FINEIBT
2421	def_bool y
2422	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2423	select CALL_PADDING
2424
2425config FINEIBT_BHI
2426	def_bool y
2427	depends on FINEIBT && CC_HAS_KCFI_ARITY
2428
2429config HAVE_CALL_THUNKS
2430	def_bool y
2431	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2432
2433config CALL_THUNKS
2434	def_bool n
2435	select CALL_PADDING
2436
2437config PREFIX_SYMBOLS
2438	def_bool y
2439	depends on CALL_PADDING && !CFI_CLANG
2440
2441menuconfig CPU_MITIGATIONS
2442	bool "Mitigations for CPU vulnerabilities"
2443	default y
2444	help
2445	  Say Y here to enable options which enable mitigations for hardware
2446	  vulnerabilities (usually related to speculative execution).
2447	  Mitigations can be disabled or restricted to SMT systems at runtime
2448	  via the "mitigations" kernel parameter.
2449
2450	  If you say N, all mitigations will be disabled.  This CANNOT be
2451	  overridden at runtime.
2452
2453	  Say 'Y', unless you really know what you are doing.
2454
2455if CPU_MITIGATIONS
2456
2457config MITIGATION_PAGE_TABLE_ISOLATION
2458	bool "Remove the kernel mapping in user mode"
2459	default y
2460	depends on (X86_64 || X86_PAE)
2461	help
2462	  This feature reduces the number of hardware side channels by
2463	  ensuring that the majority of kernel addresses are not mapped
2464	  into userspace.
2465
2466	  See Documentation/arch/x86/pti.rst for more details.
2467
2468config MITIGATION_RETPOLINE
2469	bool "Avoid speculative indirect branches in kernel"
2470	select OBJTOOL if HAVE_OBJTOOL
2471	default y
2472	help
2473	  Compile kernel with the retpoline compiler options to guard against
2474	  kernel-to-user data leaks by avoiding speculative indirect
2475	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2476	  support for full protection. The kernel may run slower.
2477
2478config MITIGATION_RETHUNK
2479	bool "Enable return-thunks"
2480	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2481	select OBJTOOL if HAVE_OBJTOOL
2482	default y if X86_64
2483	help
2484	  Compile the kernel with the return-thunks compiler option to guard
2485	  against kernel-to-user data leaks by avoiding return speculation.
2486	  Requires a compiler with -mfunction-return=thunk-extern
2487	  support for full protection. The kernel may run slower.
2488
2489config MITIGATION_UNRET_ENTRY
2490	bool "Enable UNRET on kernel entry"
2491	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2492	default y
2493	help
2494	  Compile the kernel with support for the retbleed=unret mitigation.
2495
2496config MITIGATION_CALL_DEPTH_TRACKING
2497	bool "Mitigate RSB underflow with call depth tracking"
2498	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2499	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2500	select CALL_THUNKS
2501	default y
2502	help
2503	  Compile the kernel with call depth tracking to mitigate the Intel
2504	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2505	  by default and needs to be enabled on the kernel command line via the
2506	  retbleed=stuff option. For non-affected systems the overhead of this
2507	  option is marginal as the call depth tracking is using run-time
2508	  generated call thunks in a compiler generated padding area and call
2509	  patching. This increases text size by ~5%. For non affected systems
2510	  this space is unused. On affected SKL systems this results in a
2511	  significant performance gain over the IBRS mitigation.
2512
2513config CALL_THUNKS_DEBUG
2514	bool "Enable call thunks and call depth tracking debugging"
2515	depends on MITIGATION_CALL_DEPTH_TRACKING
2516	select FUNCTION_ALIGNMENT_32B
2517	default n
2518	help
2519	  Enable call/ret counters for imbalance detection and build in
2520	  a noisy dmesg about callthunks generation and call patching for
2521	  trouble shooting. The debug prints need to be enabled on the
2522	  kernel command line with 'debug-callthunks'.
2523	  Only enable this when you are debugging call thunks as this
2524	  creates a noticeable runtime overhead. If unsure say N.
2525
2526config MITIGATION_IBPB_ENTRY
2527	bool "Enable IBPB on kernel entry"
2528	depends on CPU_SUP_AMD && X86_64
2529	default y
2530	help
2531	  Compile the kernel with support for the retbleed=ibpb and
2532	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2533
2534config MITIGATION_IBRS_ENTRY
2535	bool "Enable IBRS on kernel entry"
2536	depends on CPU_SUP_INTEL && X86_64
2537	default y
2538	help
2539	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2540	  This mitigates both spectre_v2 and retbleed at great cost to
2541	  performance.
2542
2543config MITIGATION_SRSO
2544	bool "Mitigate speculative RAS overflow on AMD"
2545	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2546	default y
2547	help
2548	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2549
2550config MITIGATION_SLS
2551	bool "Mitigate Straight-Line-Speculation"
2552	depends on CC_HAS_SLS && X86_64
2553	select OBJTOOL if HAVE_OBJTOOL
2554	default n
2555	help
2556	  Compile the kernel with straight-line-speculation options to guard
2557	  against straight line speculation. The kernel image might be slightly
2558	  larger.
2559
2560config MITIGATION_GDS
2561	bool "Mitigate Gather Data Sampling"
2562	depends on CPU_SUP_INTEL
2563	default y
2564	help
2565	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2566	  vulnerability which allows unprivileged speculative access to data
2567	  which was previously stored in vector registers. The attacker uses gather
2568	  instructions to infer the stale vector register data.
2569
2570config MITIGATION_RFDS
2571	bool "RFDS Mitigation"
2572	depends on CPU_SUP_INTEL
2573	default y
2574	help
2575	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2576	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2577	  allows unprivileged speculative access to stale data previously
2578	  stored in floating point, vector and integer registers.
2579	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2580
2581config MITIGATION_SPECTRE_BHI
2582	bool "Mitigate Spectre-BHB (Branch History Injection)"
2583	depends on CPU_SUP_INTEL
2584	default y
2585	help
2586	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2587	  where the branch history buffer is poisoned to speculatively steer
2588	  indirect branches.
2589	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2590
2591config MITIGATION_MDS
2592	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2593	depends on CPU_SUP_INTEL
2594	default y
2595	help
2596	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2597	  a hardware vulnerability which allows unprivileged speculative access
2598	  to data which is available in various CPU internal buffers.
2599	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2600
2601config MITIGATION_TAA
2602	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2603	depends on CPU_SUP_INTEL
2604	default y
2605	help
2606	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2607	  vulnerability that allows unprivileged speculative access to data
2608	  which is available in various CPU internal buffers by using
2609	  asynchronous aborts within an Intel TSX transactional region.
2610	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2611
2612config MITIGATION_MMIO_STALE_DATA
2613	bool "Mitigate MMIO Stale Data hardware bug"
2614	depends on CPU_SUP_INTEL
2615	default y
2616	help
2617	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2618	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2619	  vulnerabilities that can expose data. The vulnerabilities require the
2620	  attacker to have access to MMIO.
2621	  See also
2622	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2623
2624config MITIGATION_L1TF
2625	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2626	depends on CPU_SUP_INTEL
2627	default y
2628	help
2629	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2630	  hardware vulnerability which allows unprivileged speculative access to data
2631	  available in the Level 1 Data Cache.
2632	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2633
2634config MITIGATION_RETBLEED
2635	bool "Mitigate RETBleed hardware bug"
2636	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2637	default y
2638	help
2639	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2640	  with Return Instructions) vulnerability.  RETBleed is a speculative
2641	  execution attack which takes advantage of microarchitectural behavior
2642	  in many modern microprocessors, similar to Spectre v2. An
2643	  unprivileged attacker can use these flaws to bypass conventional
2644	  memory security restrictions to gain read access to privileged memory
2645	  that would otherwise be inaccessible.
2646
2647config MITIGATION_SPECTRE_V1
2648	bool "Mitigate SPECTRE V1 hardware bug"
2649	default y
2650	help
2651	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2652	  class of side channel attacks that takes advantage of speculative
2653	  execution that bypasses conditional branch instructions used for
2654	  memory access bounds check.
2655	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2656
2657config MITIGATION_SPECTRE_V2
2658	bool "Mitigate SPECTRE V2 hardware bug"
2659	default y
2660	help
2661	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2662	  V2 is a class of side channel attacks that takes advantage of
2663	  indirect branch predictors inside the processor. In Spectre variant 2
2664	  attacks, the attacker can steer speculative indirect branches in the
2665	  victim to gadget code by poisoning the branch target buffer of a CPU
2666	  used for predicting indirect branch addresses.
2667	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2668
2669config MITIGATION_SRBDS
2670	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2671	depends on CPU_SUP_INTEL
2672	default y
2673	help
2674	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2675	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2676	  Sampling (MDS) techniques to infer values returned from special
2677	  register accesses. An unprivileged user can extract values returned
2678	  from RDRAND and RDSEED executed on another core or sibling thread
2679	  using MDS techniques.
2680	  See also
2681	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2682
2683config MITIGATION_SSB
2684	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2685	default y
2686	help
2687	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2688	  hardware security vulnerability and its exploitation takes advantage
2689	  of speculative execution in a similar way to the Meltdown and Spectre
2690	  security vulnerabilities.
2691
2692endif
2693
2694config ARCH_HAS_ADD_PAGES
2695	def_bool y
2696	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2697
2698menu "Power management and ACPI options"
2699
2700config ARCH_HIBERNATION_HEADER
2701	def_bool y
2702	depends on HIBERNATION
2703
2704source "kernel/power/Kconfig"
2705
2706source "drivers/acpi/Kconfig"
2707
2708config X86_APM_BOOT
2709	def_bool y
2710	depends on APM
2711
2712menuconfig APM
2713	tristate "APM (Advanced Power Management) BIOS support"
2714	depends on X86_32 && PM_SLEEP
2715	help
2716	  APM is a BIOS specification for saving power using several different
2717	  techniques. This is mostly useful for battery powered laptops with
2718	  APM compliant BIOSes. If you say Y here, the system time will be
2719	  reset after a RESUME operation, the /proc/apm device will provide
2720	  battery status information, and user-space programs will receive
2721	  notification of APM "events" (e.g. battery status change).
2722
2723	  If you select "Y" here, you can disable actual use of the APM
2724	  BIOS by passing the "apm=off" option to the kernel at boot time.
2725
2726	  Note that the APM support is almost completely disabled for
2727	  machines with more than one CPU.
2728
2729	  In order to use APM, you will need supporting software. For location
2730	  and more information, read <file:Documentation/power/apm-acpi.rst>
2731	  and the Battery Powered Linux mini-HOWTO, available from
2732	  <http://www.tldp.org/docs.html#howto>.
2733
2734	  This driver does not spin down disk drives (see the hdparm(8)
2735	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2736	  VESA-compliant "green" monitors.
2737
2738	  This driver does not support the TI 4000M TravelMate and the ACER
2739	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2740	  desktop machines also don't have compliant BIOSes, and this driver
2741	  may cause those machines to panic during the boot phase.
2742
2743	  Generally, if you don't have a battery in your machine, there isn't
2744	  much point in using this driver and you should say N. If you get
2745	  random kernel OOPSes or reboots that don't seem to be related to
2746	  anything, try disabling/enabling this option (or disabling/enabling
2747	  APM in your BIOS).
2748
2749	  Some other things you should try when experiencing seemingly random,
2750	  "weird" problems:
2751
2752	  1) make sure that you have enough swap space and that it is
2753	  enabled.
2754	  2) pass the "idle=poll" option to the kernel
2755	  3) switch on floating point emulation in the kernel and pass
2756	  the "no387" option to the kernel
2757	  4) pass the "floppy=nodma" option to the kernel
2758	  5) pass the "mem=4M" option to the kernel (thereby disabling
2759	  all but the first 4 MB of RAM)
2760	  6) make sure that the CPU is not over clocked.
2761	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2762	  8) disable the cache from your BIOS settings
2763	  9) install a fan for the video card or exchange video RAM
2764	  10) install a better fan for the CPU
2765	  11) exchange RAM chips
2766	  12) exchange the motherboard.
2767
2768	  To compile this driver as a module, choose M here: the
2769	  module will be called apm.
2770
2771if APM
2772
2773config APM_IGNORE_USER_SUSPEND
2774	bool "Ignore USER SUSPEND"
2775	help
2776	  This option will ignore USER SUSPEND requests. On machines with a
2777	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2778	  series notebooks, it is necessary to say Y because of a BIOS bug.
2779
2780config APM_DO_ENABLE
2781	bool "Enable PM at boot time"
2782	help
2783	  Enable APM features at boot time. From page 36 of the APM BIOS
2784	  specification: "When disabled, the APM BIOS does not automatically
2785	  power manage devices, enter the Standby State, enter the Suspend
2786	  State, or take power saving steps in response to CPU Idle calls."
2787	  This driver will make CPU Idle calls when Linux is idle (unless this
2788	  feature is turned off -- see "Do CPU IDLE calls", below). This
2789	  should always save battery power, but more complicated APM features
2790	  will be dependent on your BIOS implementation. You may need to turn
2791	  this option off if your computer hangs at boot time when using APM
2792	  support, or if it beeps continuously instead of suspending. Turn
2793	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2794	  T400CDT. This is off by default since most machines do fine without
2795	  this feature.
2796
2797config APM_CPU_IDLE
2798	depends on CPU_IDLE
2799	bool "Make CPU Idle calls when idle"
2800	help
2801	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2802	  On some machines, this can activate improved power savings, such as
2803	  a slowed CPU clock rate, when the machine is idle. These idle calls
2804	  are made after the idle loop has run for some length of time (e.g.,
2805	  333 mS). On some machines, this will cause a hang at boot time or
2806	  whenever the CPU becomes idle. (On machines with more than one CPU,
2807	  this option does nothing.)
2808
2809config APM_DISPLAY_BLANK
2810	bool "Enable console blanking using APM"
2811	help
2812	  Enable console blanking using the APM. Some laptops can use this to
2813	  turn off the LCD backlight when the screen blanker of the Linux
2814	  virtual console blanks the screen. Note that this is only used by
2815	  the virtual console screen blanker, and won't turn off the backlight
2816	  when using the X Window system. This also doesn't have anything to
2817	  do with your VESA-compliant power-saving monitor. Further, this
2818	  option doesn't work for all laptops -- it might not turn off your
2819	  backlight at all, or it might print a lot of errors to the console,
2820	  especially if you are using gpm.
2821
2822config APM_ALLOW_INTS
2823	bool "Allow interrupts during APM BIOS calls"
2824	help
2825	  Normally we disable external interrupts while we are making calls to
2826	  the APM BIOS as a measure to lessen the effects of a badly behaving
2827	  BIOS implementation.  The BIOS should reenable interrupts if it
2828	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2829	  many of the newer IBM Thinkpads.  If you experience hangs when you
2830	  suspend, try setting this to Y.  Otherwise, say N.
2831
2832endif # APM
2833
2834source "drivers/cpufreq/Kconfig"
2835
2836source "drivers/cpuidle/Kconfig"
2837
2838source "drivers/idle/Kconfig"
2839
2840endmenu
2841
2842menu "Bus options (PCI etc.)"
2843
2844choice
2845	prompt "PCI access mode"
2846	depends on X86_32 && PCI
2847	default PCI_GOANY
2848	help
2849	  On PCI systems, the BIOS can be used to detect the PCI devices and
2850	  determine their configuration. However, some old PCI motherboards
2851	  have BIOS bugs and may crash if this is done. Also, some embedded
2852	  PCI-based systems don't have any BIOS at all. Linux can also try to
2853	  detect the PCI hardware directly without using the BIOS.
2854
2855	  With this option, you can specify how Linux should detect the
2856	  PCI devices. If you choose "BIOS", the BIOS will be used,
2857	  if you choose "Direct", the BIOS won't be used, and if you
2858	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2859	  If you choose "Any", the kernel will try MMCONFIG, then the
2860	  direct access method and falls back to the BIOS if that doesn't
2861	  work. If unsure, go with the default, which is "Any".
2862
2863config PCI_GOBIOS
2864	bool "BIOS"
2865
2866config PCI_GOMMCONFIG
2867	bool "MMConfig"
2868
2869config PCI_GODIRECT
2870	bool "Direct"
2871
2872config PCI_GOOLPC
2873	bool "OLPC XO-1"
2874	depends on OLPC
2875
2876config PCI_GOANY
2877	bool "Any"
2878
2879endchoice
2880
2881config PCI_BIOS
2882	def_bool y
2883	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2884
2885# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2886config PCI_DIRECT
2887	def_bool y
2888	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2889
2890config PCI_MMCONFIG
2891	bool "Support mmconfig PCI config space access" if X86_64
2892	default y
2893	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2894	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2895
2896config PCI_OLPC
2897	def_bool y
2898	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2899
2900config PCI_XEN
2901	def_bool y
2902	depends on PCI && XEN
2903
2904config MMCONF_FAM10H
2905	def_bool y
2906	depends on X86_64 && PCI_MMCONFIG && ACPI
2907
2908config PCI_CNB20LE_QUIRK
2909	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2910	depends on PCI
2911	help
2912	  Read the PCI windows out of the CNB20LE host bridge. This allows
2913	  PCI hotplug to work on systems with the CNB20LE chipset which do
2914	  not have ACPI.
2915
2916	  There's no public spec for this chipset, and this functionality
2917	  is known to be incomplete.
2918
2919	  You should say N unless you know you need this.
2920
2921config ISA_BUS
2922	bool "ISA bus support on modern systems" if EXPERT
2923	help
2924	  Expose ISA bus device drivers and options available for selection and
2925	  configuration. Enable this option if your target machine has an ISA
2926	  bus. ISA is an older system, displaced by PCI and newer bus
2927	  architectures -- if your target machine is modern, it probably does
2928	  not have an ISA bus.
2929
2930	  If unsure, say N.
2931
2932# x86_64 have no ISA slots, but can have ISA-style DMA.
2933config ISA_DMA_API
2934	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2935	default y
2936	help
2937	  Enables ISA-style DMA support for devices requiring such controllers.
2938	  If unsure, say Y.
2939
2940if X86_32
2941
2942config ISA
2943	bool "ISA support"
2944	help
2945	  Find out whether you have ISA slots on your motherboard.  ISA is the
2946	  name of a bus system, i.e. the way the CPU talks to the other stuff
2947	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2948	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2949	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2950
2951config SCx200
2952	tristate "NatSemi SCx200 support"
2953	help
2954	  This provides basic support for National Semiconductor's
2955	  (now AMD's) Geode processors.  The driver probes for the
2956	  PCI-IDs of several on-chip devices, so its a good dependency
2957	  for other scx200_* drivers.
2958
2959	  If compiled as a module, the driver is named scx200.
2960
2961config SCx200HR_TIMER
2962	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2963	depends on SCx200
2964	default y
2965	help
2966	  This driver provides a clocksource built upon the on-chip
2967	  27MHz high-resolution timer.  Its also a workaround for
2968	  NSC Geode SC-1100's buggy TSC, which loses time when the
2969	  processor goes idle (as is done by the scheduler).  The
2970	  other workaround is idle=poll boot option.
2971
2972config OLPC
2973	bool "One Laptop Per Child support"
2974	depends on !X86_PAE
2975	select GPIOLIB
2976	select OF
2977	select OF_PROMTREE
2978	select IRQ_DOMAIN
2979	select OLPC_EC
2980	help
2981	  Add support for detecting the unique features of the OLPC
2982	  XO hardware.
2983
2984config OLPC_XO1_PM
2985	bool "OLPC XO-1 Power Management"
2986	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2987	help
2988	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2989
2990config OLPC_XO1_RTC
2991	bool "OLPC XO-1 Real Time Clock"
2992	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2993	help
2994	  Add support for the XO-1 real time clock, which can be used as a
2995	  programmable wakeup source.
2996
2997config OLPC_XO1_SCI
2998	bool "OLPC XO-1 SCI extras"
2999	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3000	depends on INPUT=y
3001	select POWER_SUPPLY
3002	help
3003	  Add support for SCI-based features of the OLPC XO-1 laptop:
3004	   - EC-driven system wakeups
3005	   - Power button
3006	   - Ebook switch
3007	   - Lid switch
3008	   - AC adapter status updates
3009	   - Battery status updates
3010
3011config OLPC_XO15_SCI
3012	bool "OLPC XO-1.5 SCI extras"
3013	depends on OLPC && ACPI
3014	select POWER_SUPPLY
3015	help
3016	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3017	   - EC-driven system wakeups
3018	   - AC adapter status updates
3019	   - Battery status updates
3020
3021config GEODE_COMMON
3022	bool
3023
3024config ALIX
3025	bool "PCEngines ALIX System Support (LED setup)"
3026	select GPIOLIB
3027	select GEODE_COMMON
3028	help
3029	  This option enables system support for the PCEngines ALIX.
3030	  At present this just sets up LEDs for GPIO control on
3031	  ALIX2/3/6 boards.  However, other system specific setup should
3032	  get added here.
3033
3034	  Note: You must still enable the drivers for GPIO and LED support
3035	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3036
3037	  Note: You have to set alix.force=1 for boards with Award BIOS.
3038
3039config NET5501
3040	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3041	select GPIOLIB
3042	select GEODE_COMMON
3043	help
3044	  This option enables system support for the Soekris Engineering net5501.
3045
3046config GEOS
3047	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3048	select GPIOLIB
3049	select GEODE_COMMON
3050	depends on DMI
3051	help
3052	  This option enables system support for the Traverse Technologies GEOS.
3053
3054config TS5500
3055	bool "Technologic Systems TS-5500 platform support"
3056	depends on MELAN
3057	select CHECK_SIGNATURE
3058	select NEW_LEDS
3059	select LEDS_CLASS
3060	help
3061	  This option enables system support for the Technologic Systems TS-5500.
3062
3063endif # X86_32
3064
3065config AMD_NB
3066	def_bool y
3067	depends on AMD_NODE
3068
3069config AMD_NODE
3070	def_bool y
3071	depends on CPU_SUP_AMD && PCI
3072
3073endmenu
3074
3075menu "Binary Emulations"
3076
3077config IA32_EMULATION
3078	bool "IA32 Emulation"
3079	depends on X86_64
3080	select ARCH_WANT_OLD_COMPAT_IPC
3081	select BINFMT_ELF
3082	select COMPAT_OLD_SIGACTION
3083	help
3084	  Include code to run legacy 32-bit programs under a
3085	  64-bit kernel. You should likely turn this on, unless you're
3086	  100% sure that you don't have any 32-bit programs left.
3087
3088config IA32_EMULATION_DEFAULT_DISABLED
3089	bool "IA32 emulation disabled by default"
3090	default n
3091	depends on IA32_EMULATION
3092	help
3093	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3094	  processes and access to 32-bit syscalls. If unsure, leave it to its
3095	  default value.
3096
3097config X86_X32_ABI
3098	bool "x32 ABI for 64-bit mode"
3099	depends on X86_64
3100	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3101	# compressed debug sections to x86_x32 properly:
3102	# https://github.com/ClangBuiltLinux/linux/issues/514
3103	# https://github.com/ClangBuiltLinux/linux/issues/1141
3104	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3105	help
3106	  Include code to run binaries for the x32 native 32-bit ABI
3107	  for 64-bit processors.  An x32 process gets access to the
3108	  full 64-bit register file and wide data path while leaving
3109	  pointers at 32 bits for smaller memory footprint.
3110
3111config COMPAT_32
3112	def_bool y
3113	depends on IA32_EMULATION || X86_32
3114	select HAVE_UID16
3115	select OLD_SIGSUSPEND3
3116
3117config COMPAT
3118	def_bool y
3119	depends on IA32_EMULATION || X86_X32_ABI
3120
3121config COMPAT_FOR_U64_ALIGNMENT
3122	def_bool y
3123	depends on COMPAT
3124
3125endmenu
3126
3127config HAVE_ATOMIC_IOMAP
3128	def_bool y
3129	depends on X86_32
3130
3131source "arch/x86/kvm/Kconfig"
3132
3133source "arch/x86/Kconfig.cpufeatures"
3134
3135source "arch/x86/Kconfig.assembler"
3136