xref: /linux/arch/x86/Kconfig (revision 03f76ddff5b04a808ae16c06418460151e2fdd4b)
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_MSEAL_SYSTEM_MAPPINGS
30	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
31	select ARCH_SUPPORTS_PER_VMA_LOCK
32	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
33	select HAVE_ARCH_SOFT_DIRTY
34	select MODULES_USE_ELF_RELA
35	select NEED_DMA_MAP_STATE
36	select SWIOTLB
37	select ARCH_HAS_ELFCORE_COMPAT
38	select ZONE_DMA32
39	select EXECMEM if DYNAMIC_FTRACE
40	select ACPI_MRRM if ACPI
41
42config FORCE_DYNAMIC_FTRACE
43	def_bool y
44	depends on X86_32
45	depends on FUNCTION_TRACER
46	select DYNAMIC_FTRACE
47	help
48	  We keep the static function tracing (!DYNAMIC_FTRACE) around
49	  in order to test the non static function tracing in the
50	  generic code, as other architectures still use it. But we
51	  only need to keep it around for x86_64. No need to keep it
52	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
53#
54# Arch settings
55#
56# ( Note that options that are marked 'if X86_64' could in principle be
57#   ported to 32-bit as well. )
58#
59config X86
60	def_bool y
61	#
62	# Note: keep this list sorted alphabetically
63	#
64	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
65	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
66	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
67	select ARCH_32BIT_OFF_T			if X86_32
68	select ARCH_CLOCKSOURCE_INIT
69	select ARCH_CONFIGURES_CPU_MITIGATIONS
70	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
71	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
72	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
73	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
74	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
75	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
76	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
77	select ARCH_HAS_CPU_ATTACK_VECTORS	if CPU_MITIGATIONS
78	select ARCH_HAS_CACHE_LINE_SIZE
79	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
80	select ARCH_HAS_CPU_FINALIZE_INIT
81	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
82	select ARCH_HAS_CURRENT_STACK_POINTER
83	select ARCH_HAS_DEBUG_VIRTUAL
84	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
85	select ARCH_HAS_DEVMEM_IS_ALLOWED
86	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
87	select ARCH_HAS_EARLY_DEBUG		if KGDB
88	select ARCH_HAS_ELF_RANDOMIZE
89	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
90	select ARCH_HAS_FAST_MULTIPLIER
91	select ARCH_HAS_FORTIFY_SOURCE
92	select ARCH_HAS_GCOV_PROFILE_ALL
93	select ARCH_HAS_KCOV			if X86_64
94	select ARCH_HAS_KERNEL_FPU_SUPPORT
95	select ARCH_HAS_MEM_ENCRYPT
96	select ARCH_HAS_MEMBARRIER_SYNC_CORE
97	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
98	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
99	select ARCH_HAS_PMEM_API		if X86_64
100	select ARCH_HAS_PREEMPT_LAZY
101	select ARCH_HAS_PTDUMP
102	select ARCH_HAS_PTE_SPECIAL
103	select ARCH_HAS_HW_PTE_YOUNG
104	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
105	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
106	select ARCH_HAS_COPY_MC			if X86_64
107	select ARCH_HAS_SET_MEMORY
108	select ARCH_HAS_SET_DIRECT_MAP
109	select ARCH_HAS_STRICT_KERNEL_RWX
110	select ARCH_HAS_STRICT_MODULE_RWX
111	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
112	select ARCH_HAS_SYSCALL_WRAPPER
113	select ARCH_HAS_UBSAN
114	select ARCH_HAS_DEBUG_WX
115	select ARCH_HAS_ZONE_DMA_SET if EXPERT
116	select ARCH_HAVE_NMI_SAFE_CMPXCHG
117	select ARCH_HAVE_EXTRA_ELF_NOTES
118	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
119	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
120	select ARCH_MIGHT_HAVE_PC_PARPORT
121	select ARCH_MIGHT_HAVE_PC_SERIO
122	select ARCH_STACKWALK
123	select ARCH_SUPPORTS_ACPI
124	select ARCH_SUPPORTS_ATOMIC_RMW
125	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
126	select ARCH_SUPPORTS_HUGETLBFS
127	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
128	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
129	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
130	select ARCH_SUPPORTS_CFI		if X86_64
131	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI
132	select ARCH_SUPPORTS_LTO_CLANG
133	select ARCH_SUPPORTS_LTO_CLANG_THIN
134	select ARCH_SUPPORTS_RT
135	select ARCH_SUPPORTS_AUTOFDO_CLANG
136	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
137	select ARCH_USE_BUILTIN_BSWAP
138	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
139	select ARCH_USE_MEMTEST
140	select ARCH_USE_QUEUED_RWLOCKS
141	select ARCH_USE_QUEUED_SPINLOCKS
142	select ARCH_USE_SYM_ANNOTATIONS
143	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
144	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
145	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
146	select ARCH_WANTS_NO_INSTR
147	select ARCH_WANT_GENERAL_HUGETLB
148	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
149	select ARCH_WANT_LD_ORPHAN_WARN
150	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
151	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
152	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
153	select ARCH_WANTS_THP_SWAP		if X86_64
154	select ARCH_HAS_PARANOID_L1D_FLUSH
155	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
156	select BUILDTIME_TABLE_SORT
157	select CLKEVT_I8253
158	select CLOCKSOURCE_WATCHDOG
159	# Word-size accesses may read uninitialized data past the trailing \0
160	# in strings and cause false KMSAN reports.
161	select DCACHE_WORD_ACCESS		if !KMSAN
162	select DYNAMIC_SIGFRAME
163	select EDAC_ATOMIC_SCRUB
164	select EDAC_SUPPORT
165	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
166	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
167	select GENERIC_CLOCKEVENTS_MIN_ADJUST
168	select GENERIC_CMOS_UPDATE
169	select GENERIC_CPU_AUTOPROBE
170	select GENERIC_CPU_DEVICES
171	select GENERIC_CPU_VULNERABILITIES
172	select GENERIC_EARLY_IOREMAP
173	select GENERIC_ENTRY
174	select GENERIC_IOMAP
175	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
176	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
177	select GENERIC_IRQ_MIGRATION		if SMP
178	select GENERIC_IRQ_PROBE
179	select GENERIC_IRQ_RESERVATION_MODE
180	select GENERIC_IRQ_SHOW
181	select GENERIC_PENDING_IRQ		if SMP
182	select GENERIC_SMP_IDLE_THREAD
183	select GENERIC_TIME_VSYSCALL
184	select GENERIC_GETTIMEOFDAY
185	select GENERIC_VDSO_DATA_STORE
186	select GENERIC_VDSO_TIME_NS
187	select GENERIC_VDSO_OVERFLOW_PROTECT
188	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
189	select HARDIRQS_SW_RESEND
190	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
191	select HAS_IOPORT
192	select HAVE_ACPI_APEI			if ACPI
193	select HAVE_ACPI_APEI_NMI		if ACPI
194	select HAVE_ALIGNED_STRUCT_PAGE
195	select HAVE_ARCH_AUDITSYSCALL
196	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
197	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
198	select HAVE_ARCH_JUMP_LABEL
199	select HAVE_ARCH_JUMP_LABEL_RELATIVE
200	select HAVE_ARCH_KASAN			if X86_64
201	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
202	select HAVE_ARCH_KFENCE
203	select HAVE_ARCH_KMSAN			if X86_64
204	select HAVE_ARCH_KGDB
205	select HAVE_ARCH_KSTACK_ERASE
206	select HAVE_ARCH_MMAP_RND_BITS		if MMU
207	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
208	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
209	select HAVE_ARCH_PREL32_RELOCATIONS
210	select HAVE_ARCH_SECCOMP_FILTER
211	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
212	select HAVE_ARCH_TRACEHOOK
213	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
214	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
215	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
216	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
217	select HAVE_ARCH_VMAP_STACK		if X86_64
218	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
219	select HAVE_ARCH_WITHIN_STACK_FRAMES
220	select HAVE_ASM_MODVERSIONS
221	select HAVE_CMPXCHG_DOUBLE
222	select HAVE_CMPXCHG_LOCAL
223	select HAVE_CONTEXT_TRACKING_USER		if X86_64
224	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
225	select HAVE_C_RECORDMCOUNT
226	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
227	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
228	select HAVE_BUILDTIME_MCOUNT_SORT
229	select HAVE_DEBUG_KMEMLEAK
230	select HAVE_DMA_CONTIGUOUS
231	select HAVE_DYNAMIC_FTRACE
232	select HAVE_DYNAMIC_FTRACE_WITH_REGS
233	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
234	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
235	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
236	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
237	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
238	select HAVE_EBPF_JIT
239	select HAVE_EFFICIENT_UNALIGNED_ACCESS
240	select HAVE_EISA			if X86_32
241	select HAVE_EXIT_THREAD
242	select HAVE_GUP_FAST
243	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
244	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
245	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
246	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
247	select HAVE_FUNCTION_TRACER
248	select HAVE_GCC_PLUGINS
249	select HAVE_HW_BREAKPOINT
250	select HAVE_IOREMAP_PROT
251	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
252	select HAVE_IRQ_TIME_ACCOUNTING
253	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
254	select HAVE_KERNEL_BZIP2
255	select HAVE_KERNEL_GZIP
256	select HAVE_KERNEL_LZ4
257	select HAVE_KERNEL_LZMA
258	select HAVE_KERNEL_LZO
259	select HAVE_KERNEL_XZ
260	select HAVE_KERNEL_ZSTD
261	select HAVE_KPROBES
262	select HAVE_KPROBES_ON_FTRACE
263	select HAVE_FUNCTION_ERROR_INJECTION
264	select HAVE_KRETPROBES
265	select HAVE_RETHOOK
266	select HAVE_LIVEPATCH			if X86_64
267	select HAVE_MIXED_BREAKPOINTS_REGS
268	select HAVE_MOD_ARCH_SPECIFIC
269	select HAVE_MOVE_PMD
270	select HAVE_MOVE_PUD
271	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
272	select HAVE_NMI
273	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
274	select HAVE_OBJTOOL			if X86_64
275	select HAVE_OPTPROBES
276	select HAVE_PAGE_SIZE_4KB
277	select HAVE_PCSPKR_PLATFORM
278	select HAVE_PERF_EVENTS
279	select HAVE_PERF_EVENTS_NMI
280	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
281	select HAVE_PCI
282	select HAVE_PERF_REGS
283	select HAVE_PERF_USER_STACK_DUMP
284	select MMU_GATHER_RCU_TABLE_FREE
285	select MMU_GATHER_MERGE_VMAS
286	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
287	select HAVE_REGS_AND_STACK_ACCESS_API
288	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
289	select HAVE_FUNCTION_ARG_ACCESS_API
290	select HAVE_SETUP_PER_CPU_AREA
291	select HAVE_SOFTIRQ_ON_OWN_STACK
292	select HAVE_STACKPROTECTOR
293	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
294	select HAVE_STATIC_CALL
295	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
296	select HAVE_PREEMPT_DYNAMIC_CALL
297	select HAVE_RSEQ
298	select HAVE_RUST			if X86_64
299	select HAVE_SYSCALL_TRACEPOINTS
300	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
301	select HAVE_UNSTABLE_SCHED_CLOCK
302	select HAVE_USER_RETURN_NOTIFIER
303	select HAVE_GENERIC_VDSO
304	select VDSO_GETRANDOM			if X86_64
305	select HOTPLUG_PARALLEL			if SMP && X86_64
306	select HOTPLUG_SMT			if SMP
307	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
308	select IRQ_FORCED_THREADING
309	select LOCK_MM_AND_FIND_VMA
310	select NEED_PER_CPU_EMBED_FIRST_CHUNK
311	select NEED_PER_CPU_PAGE_FIRST_CHUNK
312	select NEED_SG_DMA_LENGTH
313	select NUMA_MEMBLKS			if NUMA
314	select PCI_DOMAINS			if PCI
315	select PCI_LOCKLESS_CONFIG		if PCI
316	select PERF_EVENTS
317	select RTC_LIB
318	select RTC_MC146818_LIB
319	select SPARSE_IRQ
320	select SYSCTL_EXCEPTION_TRACE
321	select THREAD_INFO_IN_TASK
322	select TRACE_IRQFLAGS_SUPPORT
323	select TRACE_IRQFLAGS_NMI_SUPPORT
324	select USER_STACKTRACE_SUPPORT
325	select HAVE_ARCH_KCSAN			if X86_64
326	select PROC_PID_ARCH_STATUS		if PROC_FS
327	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
328	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
329	select FUNCTION_ALIGNMENT_4B
330	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
331	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
332	select ARCH_SUPPORTS_PT_RECLAIM		if X86_64
333	select ARCH_SUPPORTS_SCHED_SMT		if SMP
334	select SCHED_SMT			if SMP
335	select ARCH_SUPPORTS_SCHED_CLUSTER	if SMP
336	select ARCH_SUPPORTS_SCHED_MC		if SMP
337
338config INSTRUCTION_DECODER
339	def_bool y
340	depends on KPROBES || PERF_EVENTS || UPROBES
341
342config OUTPUT_FORMAT
343	string
344	default "elf32-i386" if X86_32
345	default "elf64-x86-64" if X86_64
346
347config LOCKDEP_SUPPORT
348	def_bool y
349
350config STACKTRACE_SUPPORT
351	def_bool y
352
353config MMU
354	def_bool y
355
356config ARCH_MMAP_RND_BITS_MIN
357	default 28 if 64BIT
358	default 8
359
360config ARCH_MMAP_RND_BITS_MAX
361	default 32 if 64BIT
362	default 16
363
364config ARCH_MMAP_RND_COMPAT_BITS_MIN
365	default 8
366
367config ARCH_MMAP_RND_COMPAT_BITS_MAX
368	default 16
369
370config SBUS
371	bool
372
373config GENERIC_ISA_DMA
374	def_bool y
375	depends on ISA_DMA_API
376
377config GENERIC_CSUM
378	bool
379	default y if KMSAN || KASAN
380
381config GENERIC_BUG
382	def_bool y
383	depends on BUG
384	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
385
386config GENERIC_BUG_RELATIVE_POINTERS
387	bool
388
389config ARCH_MAY_HAVE_PC_FDC
390	def_bool y
391	depends on ISA_DMA_API
392
393config GENERIC_CALIBRATE_DELAY
394	def_bool y
395
396config ARCH_HAS_CPU_RELAX
397	def_bool y
398
399config ARCH_HIBERNATION_POSSIBLE
400	def_bool y
401
402config ARCH_SUSPEND_POSSIBLE
403	def_bool y
404
405config AUDIT_ARCH
406	def_bool y if X86_64
407
408config KASAN_SHADOW_OFFSET
409	hex
410	depends on KASAN
411	default 0xdffffc0000000000
412
413config HAVE_INTEL_TXT
414	def_bool y
415	depends on INTEL_IOMMU && ACPI
416
417config X86_64_SMP
418	def_bool y
419	depends on X86_64 && SMP
420
421config ARCH_SUPPORTS_UPROBES
422	def_bool y
423
424config FIX_EARLYCON_MEM
425	def_bool y
426
427config DYNAMIC_PHYSICAL_MASK
428	bool
429
430config PGTABLE_LEVELS
431	int
432	default 5 if X86_64
433	default 3 if X86_PAE
434	default 2
435
436menu "Processor type and features"
437
438config SMP
439	bool "Symmetric multi-processing support"
440	help
441	  This enables support for systems with more than one CPU. If you have
442	  a system with only one CPU, say N. If you have a system with more
443	  than one CPU, say Y.
444
445	  If you say N here, the kernel will run on uni- and multiprocessor
446	  machines, but will use only one CPU of a multiprocessor machine. If
447	  you say Y here, the kernel will run on many, but not all,
448	  uniprocessor machines. On a uniprocessor machine, the kernel
449	  will run faster if you say N here.
450
451	  Note that if you say Y here and choose architecture "586" or
452	  "Pentium" under "Processor family", the kernel will not work on 486
453	  architectures. Similarly, multiprocessor kernels for the "PPro"
454	  architecture may not work on all Pentium based boards.
455
456	  People using multiprocessor machines who say Y here should also say
457	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
458	  Management" code will be disabled if you say Y here.
459
460	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
461	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
462	  <http://www.tldp.org/docs.html#howto>.
463
464	  If you don't know what to do here, say N.
465
466config X86_X2APIC
467	bool "x2APIC interrupt controller architecture support"
468	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
469	default y
470	help
471	  x2APIC is an interrupt controller architecture, a component of which
472	  (the local APIC) is present in the CPU. It allows faster access to
473	  the local APIC and supports a larger number of CPUs in the system
474	  than the predecessors.
475
476	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
477	  in 2019, but it can be disabled by the BIOS. It is also frequently
478	  emulated in virtual machines, even when the host CPU does not support
479	  it. Support in the CPU can be checked by executing
480		grep x2apic /proc/cpuinfo
481
482	  If this configuration option is disabled, the kernel will boot with
483	  very reduced functionality and performance on some platforms that
484	  have x2APIC enabled. On the other hand, on hardware that does not
485	  support x2APIC, a kernel with this option enabled will just fallback
486	  to older APIC implementations.
487
488	  If in doubt, say Y.
489
490config X86_POSTED_MSI
491	bool "Enable MSI and MSI-x delivery by posted interrupts"
492	depends on X86_64 && IRQ_REMAP
493	help
494	  This enables MSIs that are under interrupt remapping to be delivered as
495	  posted interrupts to the host kernel. Interrupt throughput can
496	  potentially be improved by coalescing CPU notifications during high
497	  frequency bursts.
498
499	  If you don't know what to do here, say N.
500
501config X86_MPPARSE
502	bool "Enable MPS table" if ACPI
503	default y
504	depends on X86_LOCAL_APIC
505	help
506	  For old smp systems that do not have proper acpi support. Newer systems
507	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
508
509config X86_CPU_RESCTRL
510	bool "x86 CPU resource control support"
511	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
512	depends on MISC_FILESYSTEMS
513	select ARCH_HAS_CPU_RESCTRL
514	select RESCTRL_FS
515	select RESCTRL_FS_PSEUDO_LOCK
516	help
517	  Enable x86 CPU resource control support.
518
519	  Provide support for the allocation and monitoring of system resources
520	  usage by the CPU.
521
522	  Intel calls this Intel Resource Director Technology
523	  (Intel(R) RDT). More information about RDT can be found in the
524	  Intel x86 Architecture Software Developer Manual.
525
526	  AMD calls this AMD Platform Quality of Service (AMD QoS).
527	  More information about AMD QoS can be found in the AMD64 Technology
528	  Platform Quality of Service Extensions manual.
529
530	  Say N if unsure.
531
532config X86_FRED
533	bool "Flexible Return and Event Delivery"
534	depends on X86_64
535	help
536	  When enabled, try to use Flexible Return and Event Delivery
537	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
538	  ring transitions and exception/interrupt handling if the
539	  system supports it.
540
541config X86_EXTENDED_PLATFORM
542	bool "Support for extended (non-PC) x86 platforms"
543	default y
544	help
545	  If you disable this option then the kernel will only support
546	  standard PC platforms. (which covers the vast majority of
547	  systems out there.)
548
549	  If you enable this option then you'll be able to select support
550	  for the following non-PC x86 platforms, depending on the value of
551	  CONFIG_64BIT.
552
553	  32-bit platforms (CONFIG_64BIT=n):
554		Goldfish (mostly Android emulator)
555		Intel CE media processor (CE4100) SoC
556		Intel Quark
557		RDC R-321x SoC
558
559	  64-bit platforms (CONFIG_64BIT=y):
560		Numascale NumaChip
561		ScaleMP vSMP
562		SGI Ultraviolet
563		Merrifield/Moorefield MID devices
564		Goldfish (mostly Android emulator)
565
566	  If you have one of these systems, or if you want to build a
567	  generic distribution kernel, say Y here - otherwise say N.
568
569# This is an alphabetically sorted list of 64 bit extended platforms
570# Please maintain the alphabetic order if and when there are additions
571config X86_NUMACHIP
572	bool "Numascale NumaChip"
573	depends on X86_64
574	depends on X86_EXTENDED_PLATFORM
575	depends on NUMA
576	depends on SMP
577	depends on X86_X2APIC
578	depends on PCI_MMCONFIG
579	help
580	  Adds support for Numascale NumaChip large-SMP systems. Needed to
581	  enable more than ~168 cores.
582	  If you don't have one of these, you should say N here.
583
584config X86_VSMP
585	bool "ScaleMP vSMP"
586	select HYPERVISOR_GUEST
587	select PARAVIRT
588	depends on X86_64 && PCI
589	depends on X86_EXTENDED_PLATFORM
590	depends on SMP
591	help
592	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
593	  supposed to run on these EM64T-based machines.  Only choose this option
594	  if you have one of these machines.
595
596config X86_UV
597	bool "SGI Ultraviolet"
598	depends on X86_64
599	depends on X86_EXTENDED_PLATFORM
600	depends on NUMA
601	depends on EFI
602	depends on KEXEC_CORE
603	depends on X86_X2APIC
604	depends on PCI
605	help
606	  This option is needed in order to support SGI Ultraviolet systems.
607	  If you don't have one of these, you should say N here.
608
609config X86_INTEL_MID
610	bool "Intel Z34xx/Z35xx MID platform support"
611	depends on X86_EXTENDED_PLATFORM
612	depends on X86_PLATFORM_DEVICES
613	depends on PCI
614	depends on X86_64 || (EXPERT && PCI_GOANY)
615	depends on X86_IO_APIC
616	select I2C
617	select DW_APB_TIMER
618	select INTEL_SCU_PCI
619	help
620	  Select to build a kernel capable of supporting 64-bit Intel MID
621	  (Mobile Internet Device) platform systems which do not have
622	  the PCI legacy interfaces.
623
624	  The only supported devices are the 22nm Merrified (Z34xx)
625	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
626	  a small number of Android devices such as the Asus Zenfone 2,
627	  Asus FonePad 8 and Dell Venue 7.
628
629	  If you are building for a PC class system or non-MID tablet
630	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
631
632	  Intel MID platforms are based on an Intel processor and chipset which
633	  consume less power than most of the x86 derivatives.
634
635config X86_GOLDFISH
636	bool "Goldfish (Virtual Platform)"
637	depends on X86_EXTENDED_PLATFORM
638	help
639	  Enable support for the Goldfish virtual platform used primarily
640	  for Android development. Unless you are building for the Android
641	  Goldfish emulator say N here.
642
643# Following is an alphabetically sorted list of 32 bit extended platforms
644# Please maintain the alphabetic order if and when there are additions
645
646config X86_INTEL_CE
647	bool "CE4100 TV platform"
648	depends on PCI
649	depends on PCI_GODIRECT
650	depends on X86_IO_APIC
651	depends on X86_32
652	depends on X86_EXTENDED_PLATFORM
653	select X86_REBOOTFIXUPS
654	select OF
655	select OF_EARLY_FLATTREE
656	help
657	  Select for the Intel CE media processor (CE4100) SOC.
658	  This option compiles in support for the CE4100 SOC for settop
659	  boxes and media devices.
660
661config X86_INTEL_QUARK
662	bool "Intel Quark platform support"
663	depends on X86_32
664	depends on X86_EXTENDED_PLATFORM
665	depends on X86_PLATFORM_DEVICES
666	depends on X86_TSC
667	depends on PCI
668	depends on PCI_GOANY
669	depends on X86_IO_APIC
670	select IOSF_MBI
671	select INTEL_IMR
672	select COMMON_CLK
673	help
674	  Select to include support for Quark X1000 SoC.
675	  Say Y here if you have a Quark based system such as the Arduino
676	  compatible Intel Galileo.
677
678config X86_RDC321X
679	bool "RDC R-321x SoC"
680	depends on X86_32
681	depends on X86_EXTENDED_PLATFORM
682	select M486
683	select X86_REBOOTFIXUPS
684	help
685	  This option is needed for RDC R-321x system-on-chip, also known
686	  as R-8610-(G).
687	  If you don't have one of these chips, you should say N here.
688
689config X86_INTEL_LPSS
690	bool "Intel Low Power Subsystem Support"
691	depends on X86 && ACPI && PCI
692	select COMMON_CLK
693	select PINCTRL
694	select IOSF_MBI
695	help
696	  Select to build support for Intel Low Power Subsystem such as
697	  found on Intel Lynxpoint PCH. Selecting this option enables
698	  things like clock tree (common clock framework) and pincontrol
699	  which are needed by the LPSS peripheral drivers.
700
701config X86_AMD_PLATFORM_DEVICE
702	bool "AMD ACPI2Platform devices support"
703	depends on ACPI
704	select COMMON_CLK
705	select PINCTRL
706	help
707	  Select to interpret AMD specific ACPI device to platform device
708	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
709	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
710	  implemented under PINCTRL subsystem.
711
712config IOSF_MBI
713	tristate "Intel SoC IOSF Sideband support for SoC platforms"
714	depends on PCI
715	help
716	  This option enables sideband register access support for Intel SoC
717	  platforms. On these platforms the IOSF sideband is used in lieu of
718	  MSR's for some register accesses, mostly but not limited to thermal
719	  and power. Drivers may query the availability of this device to
720	  determine if they need the sideband in order to work on these
721	  platforms. The sideband is available on the following SoC products.
722	  This list is not meant to be exclusive.
723	   - BayTrail
724	   - Braswell
725	   - Quark
726
727	  You should say Y if you are running a kernel on one of these SoC's.
728
729config IOSF_MBI_DEBUG
730	bool "Enable IOSF sideband access through debugfs"
731	depends on IOSF_MBI && DEBUG_FS
732	help
733	  Select this option to expose the IOSF sideband access registers (MCR,
734	  MDR, MCRX) through debugfs to write and read register information from
735	  different units on the SoC. This is most useful for obtaining device
736	  state information for debug and analysis. As this is a general access
737	  mechanism, users of this option would have specific knowledge of the
738	  device they want to access.
739
740	  If you don't require the option or are in doubt, say N.
741
742config X86_SUPPORTS_MEMORY_FAILURE
743	def_bool y
744	# MCE code calls memory_failure():
745	depends on X86_MCE
746	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
747	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
748	depends on X86_64 || !SPARSEMEM
749	select ARCH_SUPPORTS_MEMORY_FAILURE
750
751config X86_32_IRIS
752	tristate "Eurobraille/Iris poweroff module"
753	depends on X86_32
754	help
755	  The Iris machines from EuroBraille do not have APM or ACPI support
756	  to shut themselves down properly.  A special I/O sequence is
757	  needed to do so, which is what this module does at
758	  kernel shutdown.
759
760	  This is only for Iris machines from EuroBraille.
761
762	  If unused, say N.
763
764config SCHED_OMIT_FRAME_POINTER
765	def_bool y
766	prompt "Single-depth WCHAN output"
767	depends on X86
768	help
769	  Calculate simpler /proc/<PID>/wchan values. If this option
770	  is disabled then wchan values will recurse back to the
771	  caller function. This provides more accurate wchan values,
772	  at the expense of slightly more scheduling overhead.
773
774	  If in doubt, say "Y".
775
776menuconfig HYPERVISOR_GUEST
777	bool "Linux guest support"
778	help
779	  Say Y here to enable options for running Linux under various hyper-
780	  visors. This option enables basic hypervisor detection and platform
781	  setup.
782
783	  If you say N, all options in this submenu will be skipped and
784	  disabled, and Linux guest support won't be built in.
785
786if HYPERVISOR_GUEST
787
788config PARAVIRT
789	bool "Enable paravirtualization code"
790	depends on HAVE_STATIC_CALL
791	help
792	  This changes the kernel so it can modify itself when it is run
793	  under a hypervisor, potentially improving performance significantly
794	  over full virtualization.  However, when run without a hypervisor
795	  the kernel is theoretically slower and slightly larger.
796
797config PARAVIRT_XXL
798	bool
799	depends on X86_64
800
801config PARAVIRT_DEBUG
802	bool "paravirt-ops debugging"
803	depends on PARAVIRT && DEBUG_KERNEL
804	help
805	  Enable to debug paravirt_ops internals.  Specifically, BUG if
806	  a paravirt_op is missing when it is called.
807
808config PARAVIRT_SPINLOCKS
809	bool "Paravirtualization layer for spinlocks"
810	depends on PARAVIRT && SMP
811	help
812	  Paravirtualized spinlocks allow a pvops backend to replace the
813	  spinlock implementation with something virtualization-friendly
814	  (for example, block the virtual CPU rather than spinning).
815
816	  It has a minimal impact on native kernels and gives a nice performance
817	  benefit on paravirtualized KVM / Xen kernels.
818
819	  If you are unsure how to answer this question, answer Y.
820
821config X86_HV_CALLBACK_VECTOR
822	def_bool n
823
824source "arch/x86/xen/Kconfig"
825
826config KVM_GUEST
827	bool "KVM Guest support (including kvmclock)"
828	depends on PARAVIRT
829	select PARAVIRT_CLOCK
830	select ARCH_CPUIDLE_HALTPOLL
831	select X86_HV_CALLBACK_VECTOR
832	default y
833	help
834	  This option enables various optimizations for running under the KVM
835	  hypervisor. It includes a paravirtualized clock, so that instead
836	  of relying on a PIT (or probably other) emulation by the
837	  underlying device model, the host provides the guest with
838	  timing infrastructure such as time of day, and system time
839
840config ARCH_CPUIDLE_HALTPOLL
841	def_bool n
842	prompt "Disable host haltpoll when loading haltpoll driver"
843	help
844	  If virtualized under KVM, disable host haltpoll.
845
846config PVH
847	bool "Support for running PVH guests"
848	help
849	  This option enables the PVH entry point for guest virtual machines
850	  as specified in the x86/HVM direct boot ABI.
851
852config PARAVIRT_TIME_ACCOUNTING
853	bool "Paravirtual steal time accounting"
854	depends on PARAVIRT
855	help
856	  Select this option to enable fine granularity task steal time
857	  accounting. Time spent executing other tasks in parallel with
858	  the current vCPU is discounted from the vCPU power. To account for
859	  that, there can be a small performance impact.
860
861	  If in doubt, say N here.
862
863config PARAVIRT_CLOCK
864	bool
865
866config JAILHOUSE_GUEST
867	bool "Jailhouse non-root cell support"
868	depends on X86_64 && PCI
869	select X86_PM_TIMER
870	help
871	  This option allows to run Linux as guest in a Jailhouse non-root
872	  cell. You can leave this option disabled if you only want to start
873	  Jailhouse and run Linux afterwards in the root cell.
874
875config ACRN_GUEST
876	bool "ACRN Guest support"
877	depends on X86_64
878	select X86_HV_CALLBACK_VECTOR
879	help
880	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
881	  a flexible, lightweight reference open-source hypervisor, built with
882	  real-time and safety-criticality in mind. It is built for embedded
883	  IOT with small footprint and real-time features. More details can be
884	  found in https://projectacrn.org/.
885
886config INTEL_TDX_GUEST
887	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
888	depends on X86_64 && CPU_SUP_INTEL
889	depends on X86_X2APIC
890	depends on EFI_STUB
891	depends on PARAVIRT
892	select ARCH_HAS_CC_PLATFORM
893	select X86_MEM_ENCRYPT
894	select X86_MCE
895	select UNACCEPTED_MEMORY
896	help
897	  Support running as a guest under Intel TDX.  Without this support,
898	  the guest kernel can not boot or run under TDX.
899	  TDX includes memory encryption and integrity capabilities
900	  which protect the confidentiality and integrity of guest
901	  memory contents and CPU state. TDX guests are protected from
902	  some attacks from the VMM.
903
904endif # HYPERVISOR_GUEST
905
906source "arch/x86/Kconfig.cpu"
907
908config HPET_TIMER
909	def_bool X86_64
910	prompt "HPET Timer Support" if X86_32
911	help
912	  Use the IA-PC HPET (High Precision Event Timer) to manage
913	  time in preference to the PIT and RTC, if a HPET is
914	  present.
915	  HPET is the next generation timer replacing legacy 8254s.
916	  The HPET provides a stable time base on SMP
917	  systems, unlike the TSC, but it is more expensive to access,
918	  as it is off-chip.  The interface used is documented
919	  in the HPET spec, revision 1.
920
921	  You can safely choose Y here.  However, HPET will only be
922	  activated if the platform and the BIOS support this feature.
923	  Otherwise the 8254 will be used for timing services.
924
925	  Choose N to continue using the legacy 8254 timer.
926
927config HPET_EMULATE_RTC
928	def_bool y
929	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
930
931# Mark as expert because too many people got it wrong.
932# The code disables itself when not needed.
933config DMI
934	default y
935	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
936	bool "Enable DMI scanning" if EXPERT
937	help
938	  Enabled scanning of DMI to identify machine quirks. Say Y
939	  here unless you have verified that your setup is not
940	  affected by entries in the DMI blacklist. Required by PNP
941	  BIOS code.
942
943config GART_IOMMU
944	bool "Old AMD GART IOMMU support"
945	select IOMMU_HELPER
946	select SWIOTLB
947	depends on X86_64 && PCI && AMD_NB
948	help
949	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
950	  GART based hardware IOMMUs.
951
952	  The GART supports full DMA access for devices with 32-bit access
953	  limitations, on systems with more than 3 GB. This is usually needed
954	  for USB, sound, many IDE/SATA chipsets and some other devices.
955
956	  Newer systems typically have a modern AMD IOMMU, supported via
957	  the CONFIG_AMD_IOMMU=y config option.
958
959	  In normal configurations this driver is only active when needed:
960	  there's more than 3 GB of memory and the system contains a
961	  32-bit limited device.
962
963	  If unsure, say Y.
964
965config BOOT_VESA_SUPPORT
966	bool
967	help
968	  If true, at least one selected framebuffer driver can take advantage
969	  of VESA video modes set at an early boot stage via the vga= parameter.
970
971config MAXSMP
972	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
973	depends on X86_64 && SMP && DEBUG_KERNEL
974	select CPUMASK_OFFSTACK
975	help
976	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
977	  If unsure, say N.
978
979#
980# The maximum number of CPUs supported:
981#
982# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
983# and which can be configured interactively in the
984# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
985#
986# The ranges are different on 32-bit and 64-bit kernels, depending on
987# hardware capabilities and scalability features of the kernel.
988#
989# ( If MAXSMP is enabled we just use the highest possible value and disable
990#   interactive configuration. )
991#
992
993config NR_CPUS_RANGE_BEGIN
994	int
995	default NR_CPUS_RANGE_END if MAXSMP
996	default    1 if !SMP
997	default    2
998
999config NR_CPUS_RANGE_END
1000	int
1001	depends on X86_32
1002	default    8 if  SMP
1003	default    1 if !SMP
1004
1005config NR_CPUS_RANGE_END
1006	int
1007	depends on X86_64
1008	default 8192 if  SMP && CPUMASK_OFFSTACK
1009	default  512 if  SMP && !CPUMASK_OFFSTACK
1010	default    1 if !SMP
1011
1012config NR_CPUS_DEFAULT
1013	int
1014	depends on X86_32
1015	default    8 if  SMP
1016	default    1 if !SMP
1017
1018config NR_CPUS_DEFAULT
1019	int
1020	depends on X86_64
1021	default 8192 if  MAXSMP
1022	default   64 if  SMP
1023	default    1 if !SMP
1024
1025config NR_CPUS
1026	int "Maximum number of CPUs" if SMP && !MAXSMP
1027	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1028	default NR_CPUS_DEFAULT
1029	help
1030	  This allows you to specify the maximum number of CPUs which this
1031	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1032	  supported value is 8192, otherwise the maximum value is 512.  The
1033	  minimum value which makes sense is 2.
1034
1035	  This is purely to save memory: each supported CPU adds about 8KB
1036	  to the kernel image.
1037
1038config SCHED_MC_PRIO
1039	bool "CPU core priorities scheduler support"
1040	depends on SCHED_MC
1041	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1042	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1043	select CPU_FREQ
1044	default y
1045	help
1046	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1047	  core ordering determined at manufacturing time, which allows
1048	  certain cores to reach higher turbo frequencies (when running
1049	  single threaded workloads) than others.
1050
1051	  Enabling this kernel feature teaches the scheduler about
1052	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1053	  scheduler's CPU selection logic accordingly, so that higher
1054	  overall system performance can be achieved.
1055
1056	  This feature will have no effect on CPUs without this feature.
1057
1058	  If unsure say Y here.
1059
1060config UP_LATE_INIT
1061	def_bool y
1062	depends on !SMP && X86_LOCAL_APIC
1063
1064config X86_UP_APIC
1065	bool "Local APIC support on uniprocessors" if !PCI_MSI
1066	default PCI_MSI
1067	depends on X86_32 && !SMP
1068	help
1069	  A local APIC (Advanced Programmable Interrupt Controller) is an
1070	  integrated interrupt controller in the CPU. If you have a single-CPU
1071	  system which has a processor with a local APIC, you can say Y here to
1072	  enable and use it. If you say Y here even though your machine doesn't
1073	  have a local APIC, then the kernel will still run with no slowdown at
1074	  all. The local APIC supports CPU-generated self-interrupts (timer,
1075	  performance counters), and the NMI watchdog which detects hard
1076	  lockups.
1077
1078config X86_UP_IOAPIC
1079	bool "IO-APIC support on uniprocessors"
1080	depends on X86_UP_APIC
1081	help
1082	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1083	  SMP-capable replacement for PC-style interrupt controllers. Most
1084	  SMP systems and many recent uniprocessor systems have one.
1085
1086	  If you have a single-CPU system with an IO-APIC, you can say Y here
1087	  to use it. If you say Y here even though your machine doesn't have
1088	  an IO-APIC, then the kernel will still run with no slowdown at all.
1089
1090config X86_LOCAL_APIC
1091	def_bool y
1092	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1093	select IRQ_DOMAIN_HIERARCHY
1094
1095config ACPI_MADT_WAKEUP
1096	def_bool y
1097	depends on X86_64
1098	depends on ACPI
1099	depends on SMP
1100	depends on X86_LOCAL_APIC
1101
1102config X86_IO_APIC
1103	def_bool y
1104	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1105
1106config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1107	bool "Reroute for broken boot IRQs"
1108	depends on X86_IO_APIC
1109	help
1110	  This option enables a workaround that fixes a source of
1111	  spurious interrupts. This is recommended when threaded
1112	  interrupt handling is used on systems where the generation of
1113	  superfluous "boot interrupts" cannot be disabled.
1114
1115	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1116	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1117	  kernel does during interrupt handling). On chipsets where this
1118	  boot IRQ generation cannot be disabled, this workaround keeps
1119	  the original IRQ line masked so that only the equivalent "boot
1120	  IRQ" is delivered to the CPUs. The workaround also tells the
1121	  kernel to set up the IRQ handler on the boot IRQ line. In this
1122	  way only one interrupt is delivered to the kernel. Otherwise
1123	  the spurious second interrupt may cause the kernel to bring
1124	  down (vital) interrupt lines.
1125
1126	  Only affects "broken" chipsets. Interrupt sharing may be
1127	  increased on these systems.
1128
1129config X86_MCE
1130	bool "Machine Check / overheating reporting"
1131	select GENERIC_ALLOCATOR
1132	default y
1133	help
1134	  Machine Check support allows the processor to notify the
1135	  kernel if it detects a problem (e.g. overheating, data corruption).
1136	  The action the kernel takes depends on the severity of the problem,
1137	  ranging from warning messages to halting the machine.
1138
1139config X86_MCELOG_LEGACY
1140	bool "Support for deprecated /dev/mcelog character device"
1141	depends on X86_MCE
1142	help
1143	  Enable support for /dev/mcelog which is needed by the old mcelog
1144	  userspace logging daemon. Consider switching to the new generation
1145	  rasdaemon solution.
1146
1147config X86_MCE_INTEL
1148	def_bool y
1149	prompt "Intel MCE features"
1150	depends on X86_MCE && X86_LOCAL_APIC
1151	help
1152	  Additional support for intel specific MCE features such as
1153	  the thermal monitor.
1154
1155config X86_MCE_AMD
1156	def_bool y
1157	prompt "AMD MCE features"
1158	depends on X86_MCE && X86_LOCAL_APIC
1159	help
1160	  Additional support for AMD specific MCE features such as
1161	  the DRAM Error Threshold.
1162
1163config X86_ANCIENT_MCE
1164	bool "Support for old Pentium 5 / WinChip machine checks"
1165	depends on X86_32 && X86_MCE
1166	help
1167	  Include support for machine check handling on old Pentium 5 or WinChip
1168	  systems. These typically need to be enabled explicitly on the command
1169	  line.
1170
1171config X86_MCE_THRESHOLD
1172	depends on X86_MCE_AMD || X86_MCE_INTEL
1173	def_bool y
1174
1175config X86_MCE_INJECT
1176	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1177	tristate "Machine check injector support"
1178	help
1179	  Provide support for injecting machine checks for testing purposes.
1180	  If you don't know what a machine check is and you don't do kernel
1181	  QA it is safe to say n.
1182
1183source "arch/x86/events/Kconfig"
1184
1185config X86_LEGACY_VM86
1186	bool "Legacy VM86 support"
1187	depends on X86_32
1188	help
1189	  This option allows user programs to put the CPU into V8086
1190	  mode, which is an 80286-era approximation of 16-bit real mode.
1191
1192	  Some very old versions of X and/or vbetool require this option
1193	  for user mode setting.  Similarly, DOSEMU will use it if
1194	  available to accelerate real mode DOS programs.  However, any
1195	  recent version of DOSEMU, X, or vbetool should be fully
1196	  functional even without kernel VM86 support, as they will all
1197	  fall back to software emulation. Nevertheless, if you are using
1198	  a 16-bit DOS program where 16-bit performance matters, vm86
1199	  mode might be faster than emulation and you might want to
1200	  enable this option.
1201
1202	  Note that any app that works on a 64-bit kernel is unlikely to
1203	  need this option, as 64-bit kernels don't, and can't, support
1204	  V8086 mode. This option is also unrelated to 16-bit protected
1205	  mode and is not needed to run most 16-bit programs under Wine.
1206
1207	  Enabling this option increases the complexity of the kernel
1208	  and slows down exception handling a tiny bit.
1209
1210	  If unsure, say N here.
1211
1212config VM86
1213	bool
1214	default X86_LEGACY_VM86
1215
1216config X86_16BIT
1217	bool "Enable support for 16-bit segments" if EXPERT
1218	default y
1219	depends on MODIFY_LDT_SYSCALL
1220	help
1221	  This option is required by programs like Wine to run 16-bit
1222	  protected mode legacy code on x86 processors.  Disabling
1223	  this option saves about 300 bytes on i386, or around 6K text
1224	  plus 16K runtime memory on x86-64,
1225
1226config X86_ESPFIX32
1227	def_bool y
1228	depends on X86_16BIT && X86_32
1229
1230config X86_ESPFIX64
1231	def_bool y
1232	depends on X86_16BIT && X86_64
1233
1234config X86_VSYSCALL_EMULATION
1235	bool "Enable vsyscall emulation" if EXPERT
1236	default y
1237	depends on X86_64
1238	help
1239	  This enables emulation of the legacy vsyscall page.  Disabling
1240	  it is roughly equivalent to booting with vsyscall=none, except
1241	  that it will also disable the helpful warning if a program
1242	  tries to use a vsyscall.  With this option set to N, offending
1243	  programs will just segfault, citing addresses of the form
1244	  0xffffffffff600?00.
1245
1246	  This option is required by many programs built before 2013, and
1247	  care should be used even with newer programs if set to N.
1248
1249	  Disabling this option saves about 7K of kernel size and
1250	  possibly 4K of additional runtime pagetable memory.
1251
1252config X86_IOPL_IOPERM
1253	bool "IOPERM and IOPL Emulation"
1254	default y
1255	help
1256	  This enables the ioperm() and iopl() syscalls which are necessary
1257	  for legacy applications.
1258
1259	  Legacy IOPL support is an overbroad mechanism which allows user
1260	  space aside of accessing all 65536 I/O ports also to disable
1261	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1262	  capabilities and permission from potentially active security
1263	  modules.
1264
1265	  The emulation restricts the functionality of the syscall to
1266	  only allowing the full range I/O port access, but prevents the
1267	  ability to disable interrupts from user space which would be
1268	  granted if the hardware IOPL mechanism would be used.
1269
1270config TOSHIBA
1271	tristate "Toshiba Laptop support"
1272	depends on X86_32
1273	help
1274	  This adds a driver to safely access the System Management Mode of
1275	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1276	  not work on models with a Phoenix BIOS. The System Management Mode
1277	  is used to set the BIOS and power saving options on Toshiba portables.
1278
1279	  For information on utilities to make use of this driver see the
1280	  Toshiba Linux utilities web site at:
1281	  <http://www.buzzard.org.uk/toshiba/>.
1282
1283	  Say Y if you intend to run this kernel on a Toshiba portable.
1284	  Say N otherwise.
1285
1286config X86_REBOOTFIXUPS
1287	bool "Enable X86 board specific fixups for reboot"
1288	depends on X86_32
1289	help
1290	  This enables chipset and/or board specific fixups to be done
1291	  in order to get reboot to work correctly. This is only needed on
1292	  some combinations of hardware and BIOS. The symptom, for which
1293	  this config is intended, is when reboot ends with a stalled/hung
1294	  system.
1295
1296	  Currently, the only fixup is for the Geode machines using
1297	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1298
1299	  Say Y if you want to enable the fixup. Currently, it's safe to
1300	  enable this option even if you don't need it.
1301	  Say N otherwise.
1302
1303config MICROCODE
1304	def_bool y
1305	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1306	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1307
1308config MICROCODE_INITRD32
1309	def_bool y
1310	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1311
1312config MICROCODE_LATE_LOADING
1313	bool "Late microcode loading (DANGEROUS)"
1314	default n
1315	depends on MICROCODE && SMP
1316	help
1317	  Loading microcode late, when the system is up and executing instructions
1318	  is a tricky business and should be avoided if possible. Just the sequence
1319	  of synchronizing all cores and SMT threads is one fragile dance which does
1320	  not guarantee that cores might not softlock after the loading. Therefore,
1321	  use this at your own risk. Late loading taints the kernel unless the
1322	  microcode header indicates that it is safe for late loading via the
1323	  minimal revision check. This minimal revision check can be enforced on
1324	  the kernel command line with "microcode.minrev=Y".
1325
1326config MICROCODE_LATE_FORCE_MINREV
1327	bool "Enforce late microcode loading minimal revision check"
1328	default n
1329	depends on MICROCODE_LATE_LOADING
1330	help
1331	  To prevent that users load microcode late which modifies already
1332	  in use features, newer microcode patches have a minimum revision field
1333	  in the microcode header, which tells the kernel which minimum
1334	  revision must be active in the CPU to safely load that new microcode
1335	  late into the running system. If disabled the check will not
1336	  be enforced but the kernel will be tainted when the minimal
1337	  revision check fails.
1338
1339	  This minimal revision check can also be controlled via the
1340	  "microcode.minrev" parameter on the kernel command line.
1341
1342	  If unsure say Y.
1343
1344config X86_MSR
1345	tristate "/dev/cpu/*/msr - Model-specific register support"
1346	help
1347	  This device gives privileged processes access to the x86
1348	  Model-Specific Registers (MSRs).  It is a character device with
1349	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1350	  MSR accesses are directed to a specific CPU on multi-processor
1351	  systems.
1352
1353config X86_CPUID
1354	tristate "/dev/cpu/*/cpuid - CPU information support"
1355	help
1356	  This device gives processes access to the x86 CPUID instruction to
1357	  be executed on a specific processor.  It is a character device
1358	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1359	  /dev/cpu/31/cpuid.
1360
1361config HIGHMEM4G
1362	bool "High Memory Support"
1363	depends on X86_32
1364	help
1365	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1366	  However, the address space of 32-bit x86 processors is only 4
1367	  Gigabytes large. That means that, if you have a large amount of
1368	  physical memory, not all of it can be "permanently mapped" by the
1369	  kernel. The physical memory that's not permanently mapped is called
1370	  "high memory".
1371
1372	  If you are compiling a kernel which will never run on a machine with
1373	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1374	  choice and suitable for most users). This will result in a "3GB/1GB"
1375	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1376	  space and the remaining part of the 4GB virtual memory space is used
1377	  by the kernel to permanently map as much physical memory as
1378	  possible.
1379
1380	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1381	  answer "Y" here.
1382
1383	  If unsure, say N.
1384
1385choice
1386	prompt "Memory split" if EXPERT
1387	default VMSPLIT_3G
1388	depends on X86_32
1389	help
1390	  Select the desired split between kernel and user memory.
1391
1392	  If the address range available to the kernel is less than the
1393	  physical memory installed, the remaining memory will be available
1394	  as "high memory". Accessing high memory is a little more costly
1395	  than low memory, as it needs to be mapped into the kernel first.
1396	  Note that increasing the kernel address space limits the range
1397	  available to user programs, making the address space there
1398	  tighter.  Selecting anything other than the default 3G/1G split
1399	  will also likely make your kernel incompatible with binary-only
1400	  kernel modules.
1401
1402	  If you are not absolutely sure what you are doing, leave this
1403	  option alone!
1404
1405	config VMSPLIT_3G
1406		bool "3G/1G user/kernel split"
1407	config VMSPLIT_3G_OPT
1408		depends on !X86_PAE
1409		bool "3G/1G user/kernel split (for full 1G low memory)"
1410	config VMSPLIT_2G
1411		bool "2G/2G user/kernel split"
1412	config VMSPLIT_2G_OPT
1413		depends on !X86_PAE
1414		bool "2G/2G user/kernel split (for full 2G low memory)"
1415	config VMSPLIT_1G
1416		bool "1G/3G user/kernel split"
1417endchoice
1418
1419config PAGE_OFFSET
1420	hex
1421	default 0xB0000000 if VMSPLIT_3G_OPT
1422	default 0x80000000 if VMSPLIT_2G
1423	default 0x78000000 if VMSPLIT_2G_OPT
1424	default 0x40000000 if VMSPLIT_1G
1425	default 0xC0000000
1426	depends on X86_32
1427
1428config HIGHMEM
1429	def_bool HIGHMEM4G
1430
1431config X86_PAE
1432	bool "PAE (Physical Address Extension) Support"
1433	depends on X86_32 && X86_HAVE_PAE
1434	select PHYS_ADDR_T_64BIT
1435	help
1436	  PAE is required for NX support, and furthermore enables
1437	  larger swapspace support for non-overcommit purposes. It
1438	  has the cost of more pagetable lookup overhead, and also
1439	  consumes more pagetable space per process.
1440
1441config X86_DIRECT_GBPAGES
1442	def_bool y
1443	depends on X86_64
1444	help
1445	  Certain kernel features effectively disable kernel
1446	  linear 1 GB mappings (even if the CPU otherwise
1447	  supports them), so don't confuse the user by printing
1448	  that we have them enabled.
1449
1450config X86_CPA_STATISTICS
1451	bool "Enable statistic for Change Page Attribute"
1452	depends on DEBUG_FS
1453	help
1454	  Expose statistics about the Change Page Attribute mechanism, which
1455	  helps to determine the effectiveness of preserving large and huge
1456	  page mappings when mapping protections are changed.
1457
1458config X86_MEM_ENCRYPT
1459	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1460	select DYNAMIC_PHYSICAL_MASK
1461	def_bool n
1462
1463config AMD_MEM_ENCRYPT
1464	bool "AMD Secure Memory Encryption (SME) support"
1465	depends on X86_64 && CPU_SUP_AMD
1466	depends on EFI_STUB
1467	select DMA_COHERENT_POOL
1468	select ARCH_USE_MEMREMAP_PROT
1469	select INSTRUCTION_DECODER
1470	select ARCH_HAS_CC_PLATFORM
1471	select X86_MEM_ENCRYPT
1472	select UNACCEPTED_MEMORY
1473	select CRYPTO_LIB_AESGCM
1474	help
1475	  Say yes to enable support for the encryption of system memory.
1476	  This requires an AMD processor that supports Secure Memory
1477	  Encryption (SME).
1478
1479# Common NUMA Features
1480config NUMA
1481	bool "NUMA Memory Allocation and Scheduler Support"
1482	depends on SMP
1483	depends on X86_64
1484	select USE_PERCPU_NUMA_NODE_ID
1485	select OF_NUMA if OF
1486	help
1487	  Enable NUMA (Non-Uniform Memory Access) support.
1488
1489	  The kernel will try to allocate memory used by a CPU on the
1490	  local memory controller of the CPU and add some more
1491	  NUMA awareness to the kernel.
1492
1493	  For 64-bit this is recommended if the system is Intel Core i7
1494	  (or later), AMD Opteron, or EM64T NUMA.
1495
1496	  Otherwise, you should say N.
1497
1498config AMD_NUMA
1499	def_bool y
1500	prompt "Old style AMD Opteron NUMA detection"
1501	depends on X86_64 && NUMA && PCI
1502	help
1503	  Enable AMD NUMA node topology detection.  You should say Y here if
1504	  you have a multi processor AMD system. This uses an old method to
1505	  read the NUMA configuration directly from the builtin Northbridge
1506	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1507	  which also takes priority if both are compiled in.
1508
1509config X86_64_ACPI_NUMA
1510	def_bool y
1511	prompt "ACPI NUMA detection"
1512	depends on X86_64 && NUMA && ACPI && PCI
1513	select ACPI_NUMA
1514	help
1515	  Enable ACPI SRAT based node topology detection.
1516
1517config NODES_SHIFT
1518	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1519	range 1 10
1520	default "10" if MAXSMP
1521	default "6" if X86_64
1522	default "3"
1523	depends on NUMA
1524	help
1525	  Specify the maximum number of NUMA Nodes available on the target
1526	  system.  Increases memory reserved to accommodate various tables.
1527
1528config ARCH_FLATMEM_ENABLE
1529	def_bool y
1530	depends on X86_32 && !NUMA
1531
1532config ARCH_SPARSEMEM_ENABLE
1533	def_bool y
1534	select SPARSEMEM_STATIC if X86_32
1535	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1536	select SPARSEMEM_VMEMMAP if X86_64
1537
1538config ARCH_SPARSEMEM_DEFAULT
1539	def_bool X86_64 || (NUMA && X86_32)
1540
1541config ARCH_SELECT_MEMORY_MODEL
1542	def_bool y
1543	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1544
1545config ARCH_MEMORY_PROBE
1546	bool "Enable sysfs memory/probe interface"
1547	depends on MEMORY_HOTPLUG
1548	help
1549	  This option enables a sysfs memory/probe interface for testing.
1550	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1551	  If you are unsure how to answer this question, answer N.
1552
1553config ARCH_PROC_KCORE_TEXT
1554	def_bool y
1555	depends on X86_64 && PROC_KCORE
1556
1557config ILLEGAL_POINTER_VALUE
1558	hex
1559	default 0 if X86_32
1560	default 0xdead000000000000 if X86_64
1561
1562config X86_PMEM_LEGACY_DEVICE
1563	bool
1564
1565config X86_PMEM_LEGACY
1566	tristate "Support non-standard NVDIMMs and ADR protected memory"
1567	depends on PHYS_ADDR_T_64BIT
1568	depends on BLK_DEV
1569	select X86_PMEM_LEGACY_DEVICE
1570	select NUMA_KEEP_MEMINFO if NUMA
1571	select LIBNVDIMM
1572	help
1573	  Treat memory marked using the non-standard e820 type of 12 as used
1574	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1575	  The kernel will offer these regions to the 'pmem' driver so
1576	  they can be used for persistent storage.
1577
1578	  Say Y if unsure.
1579
1580config X86_CHECK_BIOS_CORRUPTION
1581	bool "Check for low memory corruption"
1582	help
1583	  Periodically check for memory corruption in low memory, which
1584	  is suspected to be caused by BIOS.  Even when enabled in the
1585	  configuration, it is disabled at runtime.  Enable it by
1586	  setting "memory_corruption_check=1" on the kernel command
1587	  line.  By default it scans the low 64k of memory every 60
1588	  seconds; see the memory_corruption_check_size and
1589	  memory_corruption_check_period parameters in
1590	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1591
1592	  When enabled with the default parameters, this option has
1593	  almost no overhead, as it reserves a relatively small amount
1594	  of memory and scans it infrequently.  It both detects corruption
1595	  and prevents it from affecting the running system.
1596
1597	  It is, however, intended as a diagnostic tool; if repeatable
1598	  BIOS-originated corruption always affects the same memory,
1599	  you can use memmap= to prevent the kernel from using that
1600	  memory.
1601
1602config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1603	bool "Set the default setting of memory_corruption_check"
1604	depends on X86_CHECK_BIOS_CORRUPTION
1605	default y
1606	help
1607	  Set whether the default state of memory_corruption_check is
1608	  on or off.
1609
1610config MATH_EMULATION
1611	bool
1612	depends on MODIFY_LDT_SYSCALL
1613	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1614	help
1615	  Linux can emulate a math coprocessor (used for floating point
1616	  operations) if you don't have one. 486DX and Pentium processors have
1617	  a math coprocessor built in, 486SX and 386 do not, unless you added
1618	  a 487DX or 387, respectively. (The messages during boot time can
1619	  give you some hints here ["man dmesg"].) Everyone needs either a
1620	  coprocessor or this emulation.
1621
1622	  If you don't have a math coprocessor, you need to say Y here; if you
1623	  say Y here even though you have a coprocessor, the coprocessor will
1624	  be used nevertheless. (This behavior can be changed with the kernel
1625	  command line option "no387", which comes handy if your coprocessor
1626	  is broken. Try "man bootparam" or see the documentation of your boot
1627	  loader (lilo or loadlin) about how to pass options to the kernel at
1628	  boot time.) This means that it is a good idea to say Y here if you
1629	  intend to use this kernel on different machines.
1630
1631	  More information about the internals of the Linux math coprocessor
1632	  emulation can be found in <file:arch/x86/math-emu/README>.
1633
1634	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1635	  kernel, it won't hurt.
1636
1637config MTRR
1638	def_bool y
1639	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1640	help
1641	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1642	  the Memory Type Range Registers (MTRRs) may be used to control
1643	  processor access to memory ranges. This is most useful if you have
1644	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1645	  allows bus write transfers to be combined into a larger transfer
1646	  before bursting over the PCI/AGP bus. This can increase performance
1647	  of image write operations 2.5 times or more. Saying Y here creates a
1648	  /proc/mtrr file which may be used to manipulate your processor's
1649	  MTRRs. Typically the X server should use this.
1650
1651	  This code has a reasonably generic interface so that similar
1652	  control registers on other processors can be easily supported
1653	  as well:
1654
1655	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1656	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1657	  these, the ARRs are used to emulate the MTRRs.
1658	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1659	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1660	  write-combining. All of these processors are supported by this code
1661	  and it makes sense to say Y here if you have one of them.
1662
1663	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1664	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1665	  can lead to all sorts of problems, so it's good to say Y here.
1666
1667	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1668	  just add about 9 KB to your kernel.
1669
1670	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1671
1672config MTRR_SANITIZER
1673	def_bool y
1674	prompt "MTRR cleanup support"
1675	depends on MTRR
1676	help
1677	  Convert MTRR layout from continuous to discrete, so X drivers can
1678	  add writeback entries.
1679
1680	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1681	  The largest mtrr entry size for a continuous block can be set with
1682	  mtrr_chunk_size.
1683
1684	  If unsure, say Y.
1685
1686config MTRR_SANITIZER_ENABLE_DEFAULT
1687	int "MTRR cleanup enable value (0-1)"
1688	range 0 1
1689	default "0"
1690	depends on MTRR_SANITIZER
1691	help
1692	  Enable mtrr cleanup default value
1693
1694config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1695	int "MTRR cleanup spare reg num (0-7)"
1696	range 0 7
1697	default "1"
1698	depends on MTRR_SANITIZER
1699	help
1700	  mtrr cleanup spare entries default, it can be changed via
1701	  mtrr_spare_reg_nr=N on the kernel command line.
1702
1703config X86_PAT
1704	def_bool y
1705	prompt "x86 PAT support" if EXPERT
1706	depends on MTRR
1707	select ARCH_USES_PG_ARCH_2
1708	help
1709	  Use PAT attributes to setup page level cache control.
1710
1711	  PATs are the modern equivalents of MTRRs and are much more
1712	  flexible than MTRRs.
1713
1714	  Say N here if you see bootup problems (boot crash, boot hang,
1715	  spontaneous reboots) or a non-working video driver.
1716
1717	  If unsure, say Y.
1718
1719config X86_UMIP
1720	def_bool y
1721	prompt "User Mode Instruction Prevention" if EXPERT
1722	help
1723	  User Mode Instruction Prevention (UMIP) is a security feature in
1724	  some x86 processors. If enabled, a general protection fault is
1725	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1726	  executed in user mode. These instructions unnecessarily expose
1727	  information about the hardware state.
1728
1729	  The vast majority of applications do not use these instructions.
1730	  For the very few that do, software emulation is provided in
1731	  specific cases in protected and virtual-8086 modes. Emulated
1732	  results are dummy.
1733
1734config CC_HAS_IBT
1735	# GCC >= 9 and binutils >= 2.29
1736	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1737	# Clang/LLVM >= 14
1738	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1739	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1740	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1741		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1742		  $(as-instr,endbr64)
1743
1744config X86_CET
1745	def_bool n
1746	help
1747	  CET features configured (Shadow stack or IBT)
1748
1749config X86_KERNEL_IBT
1750	prompt "Indirect Branch Tracking"
1751	def_bool y
1752	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1753	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1754	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1755	select OBJTOOL
1756	select X86_CET
1757	help
1758	  Build the kernel with support for Indirect Branch Tracking, a
1759	  hardware support course-grain forward-edge Control Flow Integrity
1760	  protection. It enforces that all indirect calls must land on
1761	  an ENDBR instruction, as such, the compiler will instrument the
1762	  code with them to make this happen.
1763
1764	  In addition to building the kernel with IBT, seal all functions that
1765	  are not indirect call targets, avoiding them ever becoming one.
1766
1767	  This requires LTO like objtool runs and will slow down the build. It
1768	  does significantly reduce the number of ENDBR instructions in the
1769	  kernel image.
1770
1771config X86_INTEL_MEMORY_PROTECTION_KEYS
1772	prompt "Memory Protection Keys"
1773	def_bool y
1774	# Note: only available in 64-bit mode
1775	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1776	select ARCH_USES_HIGH_VMA_FLAGS
1777	select ARCH_HAS_PKEYS
1778	help
1779	  Memory Protection Keys provides a mechanism for enforcing
1780	  page-based protections, but without requiring modification of the
1781	  page tables when an application changes protection domains.
1782
1783	  For details, see Documentation/core-api/protection-keys.rst
1784
1785	  If unsure, say y.
1786
1787config ARCH_PKEY_BITS
1788	int
1789	default 4
1790
1791choice
1792	prompt "TSX enable mode"
1793	depends on CPU_SUP_INTEL
1794	default X86_INTEL_TSX_MODE_OFF
1795	help
1796	  Intel's TSX (Transactional Synchronization Extensions) feature
1797	  allows to optimize locking protocols through lock elision which
1798	  can lead to a noticeable performance boost.
1799
1800	  On the other hand it has been shown that TSX can be exploited
1801	  to form side channel attacks (e.g. TAA) and chances are there
1802	  will be more of those attacks discovered in the future.
1803
1804	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1805	  might override this decision by tsx=on the command line parameter.
1806	  Even with TSX enabled, the kernel will attempt to enable the best
1807	  possible TAA mitigation setting depending on the microcode available
1808	  for the particular machine.
1809
1810	  This option allows to set the default tsx mode between tsx=on, =off
1811	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1812	  details.
1813
1814	  Say off if not sure, auto if TSX is in use but it should be used on safe
1815	  platforms or on if TSX is in use and the security aspect of tsx is not
1816	  relevant.
1817
1818config X86_INTEL_TSX_MODE_OFF
1819	bool "off"
1820	help
1821	  TSX is disabled if possible - equals to tsx=off command line parameter.
1822
1823config X86_INTEL_TSX_MODE_ON
1824	bool "on"
1825	help
1826	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1827	  line parameter.
1828
1829config X86_INTEL_TSX_MODE_AUTO
1830	bool "auto"
1831	help
1832	  TSX is enabled on TSX capable HW that is believed to be safe against
1833	  side channel attacks- equals the tsx=auto command line parameter.
1834endchoice
1835
1836config X86_SGX
1837	bool "Software Guard eXtensions (SGX)"
1838	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1839	select CRYPTO_LIB_SHA256
1840	select MMU_NOTIFIER
1841	select NUMA_KEEP_MEMINFO if NUMA
1842	select XARRAY_MULTI
1843	help
1844	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1845	  that can be used by applications to set aside private regions of code
1846	  and data, referred to as enclaves. An enclave's private memory can
1847	  only be accessed by code running within the enclave. Accesses from
1848	  outside the enclave, including other enclaves, are disallowed by
1849	  hardware.
1850
1851	  If unsure, say N.
1852
1853config X86_USER_SHADOW_STACK
1854	bool "X86 userspace shadow stack"
1855	depends on AS_WRUSS
1856	depends on X86_64
1857	select ARCH_USES_HIGH_VMA_FLAGS
1858	select ARCH_HAS_USER_SHADOW_STACK
1859	select X86_CET
1860	help
1861	  Shadow stack protection is a hardware feature that detects function
1862	  return address corruption.  This helps mitigate ROP attacks.
1863	  Applications must be enabled to use it, and old userspace does not
1864	  get protection "for free".
1865
1866	  CPUs supporting shadow stacks were first released in 2020.
1867
1868	  See Documentation/arch/x86/shstk.rst for more information.
1869
1870	  If unsure, say N.
1871
1872config INTEL_TDX_HOST
1873	bool "Intel Trust Domain Extensions (TDX) host support"
1874	depends on CPU_SUP_INTEL
1875	depends on X86_64
1876	depends on KVM_INTEL
1877	depends on X86_X2APIC
1878	select ARCH_KEEP_MEMBLOCK
1879	depends on CONTIG_ALLOC
1880	depends on !KEXEC_CORE
1881	depends on X86_MCE
1882	help
1883	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1884	  host and certain physical attacks.  This option enables necessary TDX
1885	  support in the host kernel to run confidential VMs.
1886
1887	  If unsure, say N.
1888
1889config EFI
1890	bool "EFI runtime service support"
1891	depends on ACPI
1892	select UCS2_STRING
1893	select EFI_RUNTIME_WRAPPERS
1894	select ARCH_USE_MEMREMAP_PROT
1895	select EFI_RUNTIME_MAP if KEXEC_CORE
1896	help
1897	  This enables the kernel to use EFI runtime services that are
1898	  available (such as the EFI variable services).
1899
1900	  This option is only useful on systems that have EFI firmware.
1901	  In addition, you should use the latest ELILO loader available
1902	  at <http://elilo.sourceforge.net> in order to take advantage
1903	  of EFI runtime services. However, even with this option, the
1904	  resultant kernel should continue to boot on existing non-EFI
1905	  platforms.
1906
1907config EFI_STUB
1908	bool "EFI stub support"
1909	depends on EFI
1910	select RELOCATABLE
1911	help
1912	  This kernel feature allows a bzImage to be loaded directly
1913	  by EFI firmware without the use of a bootloader.
1914
1915	  See Documentation/admin-guide/efi-stub.rst for more information.
1916
1917config EFI_HANDOVER_PROTOCOL
1918	bool "EFI handover protocol (DEPRECATED)"
1919	depends on EFI_STUB
1920	default y
1921	help
1922	  Select this in order to include support for the deprecated EFI
1923	  handover protocol, which defines alternative entry points into the
1924	  EFI stub.  This is a practice that has no basis in the UEFI
1925	  specification, and requires a priori knowledge on the part of the
1926	  bootloader about Linux/x86 specific ways of passing the command line
1927	  and initrd, and where in memory those assets may be loaded.
1928
1929	  If in doubt, say Y. Even though the corresponding support is not
1930	  present in upstream GRUB or other bootloaders, most distros build
1931	  GRUB with numerous downstream patches applied, and may rely on the
1932	  handover protocol as as result.
1933
1934config EFI_MIXED
1935	bool "EFI mixed-mode support"
1936	depends on EFI_STUB && X86_64
1937	help
1938	  Enabling this feature allows a 64-bit kernel to be booted
1939	  on a 32-bit firmware, provided that your CPU supports 64-bit
1940	  mode.
1941
1942	  Note that it is not possible to boot a mixed-mode enabled
1943	  kernel via the EFI boot stub - a bootloader that supports
1944	  the EFI handover protocol must be used.
1945
1946	  If unsure, say N.
1947
1948config EFI_RUNTIME_MAP
1949	bool "Export EFI runtime maps to sysfs" if EXPERT
1950	depends on EFI
1951	help
1952	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1953	  That memory map is required by the 2nd kernel to set up EFI virtual
1954	  mappings after kexec, but can also be used for debugging purposes.
1955
1956	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1957
1958source "kernel/Kconfig.hz"
1959
1960config ARCH_SUPPORTS_KEXEC
1961	def_bool y
1962
1963config ARCH_SUPPORTS_KEXEC_FILE
1964	def_bool X86_64
1965
1966config ARCH_SELECTS_KEXEC_FILE
1967	def_bool y
1968	depends on KEXEC_FILE
1969	select HAVE_IMA_KEXEC if IMA
1970
1971config ARCH_SUPPORTS_KEXEC_PURGATORY
1972	def_bool y
1973
1974config ARCH_SUPPORTS_KEXEC_SIG
1975	def_bool y
1976
1977config ARCH_SUPPORTS_KEXEC_SIG_FORCE
1978	def_bool y
1979
1980config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
1981	def_bool y
1982
1983config ARCH_SUPPORTS_KEXEC_JUMP
1984	def_bool y
1985
1986config ARCH_SUPPORTS_KEXEC_HANDOVER
1987	def_bool X86_64
1988
1989config ARCH_SUPPORTS_CRASH_DUMP
1990	def_bool X86_64 || (X86_32 && HIGHMEM)
1991
1992config ARCH_DEFAULT_CRASH_DUMP
1993	def_bool y
1994
1995config ARCH_SUPPORTS_CRASH_HOTPLUG
1996	def_bool y
1997
1998config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
1999	def_bool CRASH_RESERVE
2000
2001config PHYSICAL_START
2002	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2003	default "0x1000000"
2004	help
2005	  This gives the physical address where the kernel is loaded.
2006
2007	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2008	  will decompress itself to above physical address and run from there.
2009	  Otherwise, bzImage will run from the address where it has been loaded
2010	  by the boot loader. The only exception is if it is loaded below the
2011	  above physical address, in which case it will relocate itself there.
2012
2013	  In normal kdump cases one does not have to set/change this option
2014	  as now bzImage can be compiled as a completely relocatable image
2015	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2016	  address. This option is mainly useful for the folks who don't want
2017	  to use a bzImage for capturing the crash dump and want to use a
2018	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2019	  to be specifically compiled to run from a specific memory area
2020	  (normally a reserved region) and this option comes handy.
2021
2022	  So if you are using bzImage for capturing the crash dump,
2023	  leave the value here unchanged to 0x1000000 and set
2024	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2025	  for capturing the crash dump change this value to start of
2026	  the reserved region.  In other words, it can be set based on
2027	  the "X" value as specified in the "crashkernel=YM@XM"
2028	  command line boot parameter passed to the panic-ed
2029	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2030	  for more details about crash dumps.
2031
2032	  Usage of bzImage for capturing the crash dump is recommended as
2033	  one does not have to build two kernels. Same kernel can be used
2034	  as production kernel and capture kernel. Above option should have
2035	  gone away after relocatable bzImage support is introduced. But it
2036	  is present because there are users out there who continue to use
2037	  vmlinux for dump capture. This option should go away down the
2038	  line.
2039
2040	  Don't change this unless you know what you are doing.
2041
2042config RELOCATABLE
2043	bool "Build a relocatable kernel"
2044	default y
2045	help
2046	  This builds a kernel image that retains relocation information
2047	  so it can be loaded someplace besides the default 1MB.
2048	  The relocations tend to make the kernel binary about 10% larger,
2049	  but are discarded at runtime.
2050
2051	  One use is for the kexec on panic case where the recovery kernel
2052	  must live at a different physical address than the primary
2053	  kernel.
2054
2055	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2056	  it has been loaded at and the compile time physical address
2057	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2058
2059config RANDOMIZE_BASE
2060	bool "Randomize the address of the kernel image (KASLR)"
2061	depends on RELOCATABLE
2062	default y
2063	help
2064	  In support of Kernel Address Space Layout Randomization (KASLR),
2065	  this randomizes the physical address at which the kernel image
2066	  is decompressed and the virtual address where the kernel
2067	  image is mapped, as a security feature that deters exploit
2068	  attempts relying on knowledge of the location of kernel
2069	  code internals.
2070
2071	  On 64-bit, the kernel physical and virtual addresses are
2072	  randomized separately. The physical address will be anywhere
2073	  between 16MB and the top of physical memory (up to 64TB). The
2074	  virtual address will be randomized from 16MB up to 1GB (9 bits
2075	  of entropy). Note that this also reduces the memory space
2076	  available to kernel modules from 1.5GB to 1GB.
2077
2078	  On 32-bit, the kernel physical and virtual addresses are
2079	  randomized together. They will be randomized from 16MB up to
2080	  512MB (8 bits of entropy).
2081
2082	  Entropy is generated using the RDRAND instruction if it is
2083	  supported. If RDTSC is supported, its value is mixed into
2084	  the entropy pool as well. If neither RDRAND nor RDTSC are
2085	  supported, then entropy is read from the i8254 timer. The
2086	  usable entropy is limited by the kernel being built using
2087	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2088	  minimum of 2MB. As a result, only 10 bits of entropy are
2089	  theoretically possible, but the implementations are further
2090	  limited due to memory layouts.
2091
2092	  If unsure, say Y.
2093
2094# Relocation on x86 needs some additional build support
2095config X86_NEED_RELOCS
2096	def_bool y
2097	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2098	select ARCH_VMLINUX_NEEDS_RELOCS
2099
2100config PHYSICAL_ALIGN
2101	hex "Alignment value to which kernel should be aligned"
2102	default "0x200000"
2103	range 0x2000 0x1000000 if X86_32
2104	range 0x200000 0x1000000 if X86_64
2105	help
2106	  This value puts the alignment restrictions on physical address
2107	  where kernel is loaded and run from. Kernel is compiled for an
2108	  address which meets above alignment restriction.
2109
2110	  If bootloader loads the kernel at a non-aligned address and
2111	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2112	  address aligned to above value and run from there.
2113
2114	  If bootloader loads the kernel at a non-aligned address and
2115	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2116	  load address and decompress itself to the address it has been
2117	  compiled for and run from there. The address for which kernel is
2118	  compiled already meets above alignment restrictions. Hence the
2119	  end result is that kernel runs from a physical address meeting
2120	  above alignment restrictions.
2121
2122	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2123	  this value must be a multiple of 0x200000.
2124
2125	  Don't change this unless you know what you are doing.
2126
2127config RANDOMIZE_MEMORY
2128	bool "Randomize the kernel memory sections"
2129	depends on X86_64
2130	depends on RANDOMIZE_BASE
2131	default RANDOMIZE_BASE
2132	help
2133	  Randomizes the base virtual address of kernel memory sections
2134	  (physical memory mapping, vmalloc & vmemmap). This security feature
2135	  makes exploits relying on predictable memory locations less reliable.
2136
2137	  The order of allocations remains unchanged. Entropy is generated in
2138	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2139	  configuration have in average 30,000 different possible virtual
2140	  addresses for each memory section.
2141
2142	  If unsure, say Y.
2143
2144config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2145	hex "Physical memory mapping padding" if EXPERT
2146	depends on RANDOMIZE_MEMORY
2147	default "0xa" if MEMORY_HOTPLUG
2148	default "0x0"
2149	range 0x1 0x40 if MEMORY_HOTPLUG
2150	range 0x0 0x40
2151	help
2152	  Define the padding in terabytes added to the existing physical
2153	  memory size during kernel memory randomization. It is useful
2154	  for memory hotplug support but reduces the entropy available for
2155	  address randomization.
2156
2157	  If unsure, leave at the default value.
2158
2159config ADDRESS_MASKING
2160	bool "Linear Address Masking support"
2161	depends on X86_64
2162	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2163	help
2164	  Linear Address Masking (LAM) modifies the checking that is applied
2165	  to 64-bit linear addresses, allowing software to use of the
2166	  untranslated address bits for metadata.
2167
2168	  The capability can be used for efficient address sanitizers (ASAN)
2169	  implementation and for optimizations in JITs.
2170
2171config HOTPLUG_CPU
2172	def_bool y
2173	depends on SMP
2174
2175config COMPAT_VDSO
2176	def_bool n
2177	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2178	depends on COMPAT_32
2179	help
2180	  Certain buggy versions of glibc will crash if they are
2181	  presented with a 32-bit vDSO that is not mapped at the address
2182	  indicated in its segment table.
2183
2184	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2185	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2186	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2187	  the only released version with the bug, but OpenSUSE 9
2188	  contains a buggy "glibc 2.3.2".
2189
2190	  The symptom of the bug is that everything crashes on startup, saying:
2191	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2192
2193	  Saying Y here changes the default value of the vdso32 boot
2194	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2195	  This works around the glibc bug but hurts performance.
2196
2197	  If unsure, say N: if you are compiling your own kernel, you
2198	  are unlikely to be using a buggy version of glibc.
2199
2200choice
2201	prompt "vsyscall table for legacy applications"
2202	depends on X86_64
2203	default LEGACY_VSYSCALL_XONLY
2204	help
2205	  Legacy user code that does not know how to find the vDSO expects
2206	  to be able to issue three syscalls by calling fixed addresses in
2207	  kernel space. Since this location is not randomized with ASLR,
2208	  it can be used to assist security vulnerability exploitation.
2209
2210	  This setting can be changed at boot time via the kernel command
2211	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2212	  is deprecated and can only be enabled using the kernel command
2213	  line.
2214
2215	  On a system with recent enough glibc (2.14 or newer) and no
2216	  static binaries, you can say None without a performance penalty
2217	  to improve security.
2218
2219	  If unsure, select "Emulate execution only".
2220
2221	config LEGACY_VSYSCALL_XONLY
2222		bool "Emulate execution only"
2223		help
2224		  The kernel traps and emulates calls into the fixed vsyscall
2225		  address mapping and does not allow reads.  This
2226		  configuration is recommended when userspace might use the
2227		  legacy vsyscall area but support for legacy binary
2228		  instrumentation of legacy code is not needed.  It mitigates
2229		  certain uses of the vsyscall area as an ASLR-bypassing
2230		  buffer.
2231
2232	config LEGACY_VSYSCALL_NONE
2233		bool "None"
2234		help
2235		  There will be no vsyscall mapping at all. This will
2236		  eliminate any risk of ASLR bypass due to the vsyscall
2237		  fixed address mapping. Attempts to use the vsyscalls
2238		  will be reported to dmesg, so that either old or
2239		  malicious userspace programs can be identified.
2240
2241endchoice
2242
2243config CMDLINE_BOOL
2244	bool "Built-in kernel command line"
2245	help
2246	  Allow for specifying boot arguments to the kernel at
2247	  build time.  On some systems (e.g. embedded ones), it is
2248	  necessary or convenient to provide some or all of the
2249	  kernel boot arguments with the kernel itself (that is,
2250	  to not rely on the boot loader to provide them.)
2251
2252	  To compile command line arguments into the kernel,
2253	  set this option to 'Y', then fill in the
2254	  boot arguments in CONFIG_CMDLINE.
2255
2256	  Systems with fully functional boot loaders (i.e. non-embedded)
2257	  should leave this option set to 'N'.
2258
2259config CMDLINE
2260	string "Built-in kernel command string"
2261	depends on CMDLINE_BOOL
2262	default ""
2263	help
2264	  Enter arguments here that should be compiled into the kernel
2265	  image and used at boot time.  If the boot loader provides a
2266	  command line at boot time, it is appended to this string to
2267	  form the full kernel command line, when the system boots.
2268
2269	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2270	  change this behavior.
2271
2272	  In most cases, the command line (whether built-in or provided
2273	  by the boot loader) should specify the device for the root
2274	  file system.
2275
2276config CMDLINE_OVERRIDE
2277	bool "Built-in command line overrides boot loader arguments"
2278	depends on CMDLINE_BOOL && CMDLINE != ""
2279	help
2280	  Set this option to 'Y' to have the kernel ignore the boot loader
2281	  command line, and use ONLY the built-in command line.
2282
2283	  This is used to work around broken boot loaders.  This should
2284	  be set to 'N' under normal conditions.
2285
2286config MODIFY_LDT_SYSCALL
2287	bool "Enable the LDT (local descriptor table)" if EXPERT
2288	default y
2289	help
2290	  Linux can allow user programs to install a per-process x86
2291	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2292	  call.  This is required to run 16-bit or segmented code such as
2293	  DOSEMU or some Wine programs.  It is also used by some very old
2294	  threading libraries.
2295
2296	  Enabling this feature adds a small amount of overhead to
2297	  context switches and increases the low-level kernel attack
2298	  surface.  Disabling it removes the modify_ldt(2) system call.
2299
2300	  Saying 'N' here may make sense for embedded or server kernels.
2301
2302config STRICT_SIGALTSTACK_SIZE
2303	bool "Enforce strict size checking for sigaltstack"
2304	depends on DYNAMIC_SIGFRAME
2305	help
2306	  For historical reasons MINSIGSTKSZ is a constant which became
2307	  already too small with AVX512 support. Add a mechanism to
2308	  enforce strict checking of the sigaltstack size against the
2309	  real size of the FPU frame. This option enables the check
2310	  by default. It can also be controlled via the kernel command
2311	  line option 'strict_sas_size' independent of this config
2312	  switch. Enabling it might break existing applications which
2313	  allocate a too small sigaltstack but 'work' because they
2314	  never get a signal delivered.
2315
2316	  Say 'N' unless you want to really enforce this check.
2317
2318config CFI_AUTO_DEFAULT
2319	bool "Attempt to use FineIBT by default at boot time"
2320	depends on FINEIBT
2321	depends on !RUST || RUSTC_VERSION >= 108800
2322	default y
2323	help
2324	  Attempt to use FineIBT by default at boot time. If enabled,
2325	  this is the same as booting with "cfi=auto". If disabled,
2326	  this is the same as booting with "cfi=kcfi".
2327
2328source "kernel/livepatch/Kconfig"
2329
2330config X86_BUS_LOCK_DETECT
2331	bool "Split Lock Detect and Bus Lock Detect support"
2332	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2333	default y
2334	help
2335	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2336	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2337
2338endmenu
2339
2340config CC_HAS_NAMED_AS
2341	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2342	depends on CC_IS_GCC
2343
2344#
2345# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2346# are incompatible with named address spaces with GCC < 13.3
2347# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2348#
2349
2350config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2351	def_bool y
2352	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2353	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2354
2355config USE_X86_SEG_SUPPORT
2356	def_bool CC_HAS_NAMED_AS
2357	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2358
2359config CC_HAS_SLS
2360	def_bool $(cc-option,-mharden-sls=all)
2361
2362config CC_HAS_RETURN_THUNK
2363	def_bool $(cc-option,-mfunction-return=thunk-extern)
2364
2365config CC_HAS_ENTRY_PADDING
2366	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2367
2368config CC_HAS_KCFI_ARITY
2369	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2370	depends on CC_IS_CLANG && !RUST
2371
2372config FUNCTION_PADDING_CFI
2373	int
2374	default 59 if FUNCTION_ALIGNMENT_64B
2375	default 27 if FUNCTION_ALIGNMENT_32B
2376	default 11 if FUNCTION_ALIGNMENT_16B
2377	default  3 if FUNCTION_ALIGNMENT_8B
2378	default  0
2379
2380# Basically: FUNCTION_ALIGNMENT - 5*CFI
2381# except Kconfig can't do arithmetic :/
2382config FUNCTION_PADDING_BYTES
2383	int
2384	default FUNCTION_PADDING_CFI if CFI
2385	default FUNCTION_ALIGNMENT
2386
2387config CALL_PADDING
2388	def_bool n
2389	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2390	select FUNCTION_ALIGNMENT_16B
2391
2392config FINEIBT
2393	def_bool y
2394	depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE
2395	select CALL_PADDING
2396
2397config FINEIBT_BHI
2398	def_bool y
2399	depends on FINEIBT && CC_HAS_KCFI_ARITY
2400
2401config HAVE_CALL_THUNKS
2402	def_bool y
2403	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2404
2405config CALL_THUNKS
2406	def_bool n
2407	select CALL_PADDING
2408
2409config PREFIX_SYMBOLS
2410	def_bool y
2411	depends on CALL_PADDING && !CFI
2412
2413menuconfig CPU_MITIGATIONS
2414	bool "Mitigations for CPU vulnerabilities"
2415	default y
2416	help
2417	  Say Y here to enable options which enable mitigations for hardware
2418	  vulnerabilities (usually related to speculative execution).
2419	  Mitigations can be disabled or restricted to SMT systems at runtime
2420	  via the "mitigations" kernel parameter.
2421
2422	  If you say N, all mitigations will be disabled.  This CANNOT be
2423	  overridden at runtime.
2424
2425	  Say 'Y', unless you really know what you are doing.
2426
2427if CPU_MITIGATIONS
2428
2429config MITIGATION_PAGE_TABLE_ISOLATION
2430	bool "Remove the kernel mapping in user mode"
2431	default y
2432	depends on (X86_64 || X86_PAE)
2433	help
2434	  This feature reduces the number of hardware side channels by
2435	  ensuring that the majority of kernel addresses are not mapped
2436	  into userspace.
2437
2438	  See Documentation/arch/x86/pti.rst for more details.
2439
2440config MITIGATION_RETPOLINE
2441	bool "Avoid speculative indirect branches in kernel"
2442	select OBJTOOL if HAVE_OBJTOOL
2443	default y
2444	help
2445	  Compile kernel with the retpoline compiler options to guard against
2446	  kernel-to-user data leaks by avoiding speculative indirect
2447	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2448	  support for full protection. The kernel may run slower.
2449
2450config MITIGATION_RETHUNK
2451	bool "Enable return-thunks"
2452	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2453	select OBJTOOL if HAVE_OBJTOOL
2454	default y if X86_64
2455	help
2456	  Compile the kernel with the return-thunks compiler option to guard
2457	  against kernel-to-user data leaks by avoiding return speculation.
2458	  Requires a compiler with -mfunction-return=thunk-extern
2459	  support for full protection. The kernel may run slower.
2460
2461config MITIGATION_UNRET_ENTRY
2462	bool "Enable UNRET on kernel entry"
2463	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2464	default y
2465	help
2466	  Compile the kernel with support for the retbleed=unret mitigation.
2467
2468config MITIGATION_CALL_DEPTH_TRACKING
2469	bool "Mitigate RSB underflow with call depth tracking"
2470	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2471	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2472	select CALL_THUNKS
2473	default y
2474	help
2475	  Compile the kernel with call depth tracking to mitigate the Intel
2476	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2477	  by default and needs to be enabled on the kernel command line via the
2478	  retbleed=stuff option. For non-affected systems the overhead of this
2479	  option is marginal as the call depth tracking is using run-time
2480	  generated call thunks in a compiler generated padding area and call
2481	  patching. This increases text size by ~5%. For non affected systems
2482	  this space is unused. On affected SKL systems this results in a
2483	  significant performance gain over the IBRS mitigation.
2484
2485config CALL_THUNKS_DEBUG
2486	bool "Enable call thunks and call depth tracking debugging"
2487	depends on MITIGATION_CALL_DEPTH_TRACKING
2488	select FUNCTION_ALIGNMENT_32B
2489	default n
2490	help
2491	  Enable call/ret counters for imbalance detection and build in
2492	  a noisy dmesg about callthunks generation and call patching for
2493	  trouble shooting. The debug prints need to be enabled on the
2494	  kernel command line with 'debug-callthunks'.
2495	  Only enable this when you are debugging call thunks as this
2496	  creates a noticeable runtime overhead. If unsure say N.
2497
2498config MITIGATION_IBPB_ENTRY
2499	bool "Enable IBPB on kernel entry"
2500	depends on CPU_SUP_AMD && X86_64
2501	default y
2502	help
2503	  Compile the kernel with support for the retbleed=ibpb and
2504	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2505
2506config MITIGATION_IBRS_ENTRY
2507	bool "Enable IBRS on kernel entry"
2508	depends on CPU_SUP_INTEL && X86_64
2509	default y
2510	help
2511	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2512	  This mitigates both spectre_v2 and retbleed at great cost to
2513	  performance.
2514
2515config MITIGATION_SRSO
2516	bool "Mitigate speculative RAS overflow on AMD"
2517	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2518	default y
2519	help
2520	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2521
2522config MITIGATION_SLS
2523	bool "Mitigate Straight-Line-Speculation"
2524	depends on CC_HAS_SLS && X86_64
2525	select OBJTOOL if HAVE_OBJTOOL
2526	default n
2527	help
2528	  Compile the kernel with straight-line-speculation options to guard
2529	  against straight line speculation. The kernel image might be slightly
2530	  larger.
2531
2532config MITIGATION_GDS
2533	bool "Mitigate Gather Data Sampling"
2534	depends on CPU_SUP_INTEL
2535	default y
2536	help
2537	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2538	  vulnerability which allows unprivileged speculative access to data
2539	  which was previously stored in vector registers. The attacker uses gather
2540	  instructions to infer the stale vector register data.
2541
2542config MITIGATION_RFDS
2543	bool "RFDS Mitigation"
2544	depends on CPU_SUP_INTEL
2545	default y
2546	help
2547	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2548	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2549	  allows unprivileged speculative access to stale data previously
2550	  stored in floating point, vector and integer registers.
2551	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2552
2553config MITIGATION_SPECTRE_BHI
2554	bool "Mitigate Spectre-BHB (Branch History Injection)"
2555	depends on CPU_SUP_INTEL
2556	default y
2557	help
2558	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2559	  where the branch history buffer is poisoned to speculatively steer
2560	  indirect branches.
2561	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2562
2563config MITIGATION_MDS
2564	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2565	depends on CPU_SUP_INTEL
2566	default y
2567	help
2568	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2569	  a hardware vulnerability which allows unprivileged speculative access
2570	  to data which is available in various CPU internal buffers.
2571	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2572
2573config MITIGATION_TAA
2574	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2575	depends on CPU_SUP_INTEL
2576	default y
2577	help
2578	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2579	  vulnerability that allows unprivileged speculative access to data
2580	  which is available in various CPU internal buffers by using
2581	  asynchronous aborts within an Intel TSX transactional region.
2582	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2583
2584config MITIGATION_MMIO_STALE_DATA
2585	bool "Mitigate MMIO Stale Data hardware bug"
2586	depends on CPU_SUP_INTEL
2587	default y
2588	help
2589	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2590	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2591	  vulnerabilities that can expose data. The vulnerabilities require the
2592	  attacker to have access to MMIO.
2593	  See also
2594	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2595
2596config MITIGATION_L1TF
2597	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2598	depends on CPU_SUP_INTEL
2599	default y
2600	help
2601	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2602	  hardware vulnerability which allows unprivileged speculative access to data
2603	  available in the Level 1 Data Cache.
2604	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2605
2606config MITIGATION_RETBLEED
2607	bool "Mitigate RETBleed hardware bug"
2608	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2609	default y
2610	help
2611	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2612	  with Return Instructions) vulnerability.  RETBleed is a speculative
2613	  execution attack which takes advantage of microarchitectural behavior
2614	  in many modern microprocessors, similar to Spectre v2. An
2615	  unprivileged attacker can use these flaws to bypass conventional
2616	  memory security restrictions to gain read access to privileged memory
2617	  that would otherwise be inaccessible.
2618
2619config MITIGATION_SPECTRE_V1
2620	bool "Mitigate SPECTRE V1 hardware bug"
2621	default y
2622	help
2623	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2624	  class of side channel attacks that takes advantage of speculative
2625	  execution that bypasses conditional branch instructions used for
2626	  memory access bounds check.
2627	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2628
2629config MITIGATION_SPECTRE_V2
2630	bool "Mitigate SPECTRE V2 hardware bug"
2631	default y
2632	help
2633	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2634	  V2 is a class of side channel attacks that takes advantage of
2635	  indirect branch predictors inside the processor. In Spectre variant 2
2636	  attacks, the attacker can steer speculative indirect branches in the
2637	  victim to gadget code by poisoning the branch target buffer of a CPU
2638	  used for predicting indirect branch addresses.
2639	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2640
2641config MITIGATION_SRBDS
2642	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2643	depends on CPU_SUP_INTEL
2644	default y
2645	help
2646	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2647	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2648	  Sampling (MDS) techniques to infer values returned from special
2649	  register accesses. An unprivileged user can extract values returned
2650	  from RDRAND and RDSEED executed on another core or sibling thread
2651	  using MDS techniques.
2652	  See also
2653	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2654
2655config MITIGATION_SSB
2656	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2657	default y
2658	help
2659	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2660	  hardware security vulnerability and its exploitation takes advantage
2661	  of speculative execution in a similar way to the Meltdown and Spectre
2662	  security vulnerabilities.
2663
2664config MITIGATION_ITS
2665	bool "Enable Indirect Target Selection mitigation"
2666	depends on CPU_SUP_INTEL && X86_64
2667	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2668	select EXECMEM
2669	default y
2670	help
2671	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2672	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2673	  disabled, mitigation cannot be enabled via cmdline.
2674	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2675
2676config MITIGATION_TSA
2677	bool "Mitigate Transient Scheduler Attacks"
2678	depends on CPU_SUP_AMD
2679	default y
2680	help
2681	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2682	  security vulnerability on AMD CPUs which can lead to forwarding of
2683	  invalid info to subsequent instructions and thus can affect their
2684	  timing and thereby cause a leakage.
2685
2686config MITIGATION_VMSCAPE
2687	bool "Mitigate VMSCAPE"
2688	depends on KVM
2689	default y
2690	help
2691	  Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security
2692	  vulnerability on Intel and AMD CPUs that may allow a guest to do
2693	  Spectre v2 style attacks on userspace hypervisor.
2694endif
2695
2696config ARCH_HAS_ADD_PAGES
2697	def_bool y
2698	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2699
2700menu "Power management and ACPI options"
2701
2702config ARCH_HIBERNATION_HEADER
2703	def_bool y
2704	depends on HIBERNATION
2705
2706source "kernel/power/Kconfig"
2707
2708source "drivers/acpi/Kconfig"
2709
2710config X86_APM_BOOT
2711	def_bool y
2712	depends on APM
2713
2714menuconfig APM
2715	tristate "APM (Advanced Power Management) BIOS support"
2716	depends on X86_32 && PM_SLEEP
2717	help
2718	  APM is a BIOS specification for saving power using several different
2719	  techniques. This is mostly useful for battery powered laptops with
2720	  APM compliant BIOSes. If you say Y here, the system time will be
2721	  reset after a RESUME operation, the /proc/apm device will provide
2722	  battery status information, and user-space programs will receive
2723	  notification of APM "events" (e.g. battery status change).
2724
2725	  If you select "Y" here, you can disable actual use of the APM
2726	  BIOS by passing the "apm=off" option to the kernel at boot time.
2727
2728	  Note that the APM support is almost completely disabled for
2729	  machines with more than one CPU.
2730
2731	  In order to use APM, you will need supporting software. For location
2732	  and more information, read <file:Documentation/power/apm-acpi.rst>
2733	  and the Battery Powered Linux mini-HOWTO, available from
2734	  <http://www.tldp.org/docs.html#howto>.
2735
2736	  This driver does not spin down disk drives (see the hdparm(8)
2737	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2738	  VESA-compliant "green" monitors.
2739
2740	  This driver does not support the TI 4000M TravelMate and the ACER
2741	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2742	  desktop machines also don't have compliant BIOSes, and this driver
2743	  may cause those machines to panic during the boot phase.
2744
2745	  Generally, if you don't have a battery in your machine, there isn't
2746	  much point in using this driver and you should say N. If you get
2747	  random kernel OOPSes or reboots that don't seem to be related to
2748	  anything, try disabling/enabling this option (or disabling/enabling
2749	  APM in your BIOS).
2750
2751	  Some other things you should try when experiencing seemingly random,
2752	  "weird" problems:
2753
2754	  1) make sure that you have enough swap space and that it is
2755	  enabled.
2756	  2) pass the "idle=poll" option to the kernel
2757	  3) switch on floating point emulation in the kernel and pass
2758	  the "no387" option to the kernel
2759	  4) pass the "floppy=nodma" option to the kernel
2760	  5) pass the "mem=4M" option to the kernel (thereby disabling
2761	  all but the first 4 MB of RAM)
2762	  6) make sure that the CPU is not over clocked.
2763	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2764	  8) disable the cache from your BIOS settings
2765	  9) install a fan for the video card or exchange video RAM
2766	  10) install a better fan for the CPU
2767	  11) exchange RAM chips
2768	  12) exchange the motherboard.
2769
2770	  To compile this driver as a module, choose M here: the
2771	  module will be called apm.
2772
2773if APM
2774
2775config APM_IGNORE_USER_SUSPEND
2776	bool "Ignore USER SUSPEND"
2777	help
2778	  This option will ignore USER SUSPEND requests. On machines with a
2779	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2780	  series notebooks, it is necessary to say Y because of a BIOS bug.
2781
2782config APM_DO_ENABLE
2783	bool "Enable PM at boot time"
2784	help
2785	  Enable APM features at boot time. From page 36 of the APM BIOS
2786	  specification: "When disabled, the APM BIOS does not automatically
2787	  power manage devices, enter the Standby State, enter the Suspend
2788	  State, or take power saving steps in response to CPU Idle calls."
2789	  This driver will make CPU Idle calls when Linux is idle (unless this
2790	  feature is turned off -- see "Do CPU IDLE calls", below). This
2791	  should always save battery power, but more complicated APM features
2792	  will be dependent on your BIOS implementation. You may need to turn
2793	  this option off if your computer hangs at boot time when using APM
2794	  support, or if it beeps continuously instead of suspending. Turn
2795	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2796	  T400CDT. This is off by default since most machines do fine without
2797	  this feature.
2798
2799config APM_CPU_IDLE
2800	depends on CPU_IDLE
2801	bool "Make CPU Idle calls when idle"
2802	help
2803	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2804	  On some machines, this can activate improved power savings, such as
2805	  a slowed CPU clock rate, when the machine is idle. These idle calls
2806	  are made after the idle loop has run for some length of time (e.g.,
2807	  333 mS). On some machines, this will cause a hang at boot time or
2808	  whenever the CPU becomes idle. (On machines with more than one CPU,
2809	  this option does nothing.)
2810
2811config APM_DISPLAY_BLANK
2812	bool "Enable console blanking using APM"
2813	help
2814	  Enable console blanking using the APM. Some laptops can use this to
2815	  turn off the LCD backlight when the screen blanker of the Linux
2816	  virtual console blanks the screen. Note that this is only used by
2817	  the virtual console screen blanker, and won't turn off the backlight
2818	  when using the X Window system. This also doesn't have anything to
2819	  do with your VESA-compliant power-saving monitor. Further, this
2820	  option doesn't work for all laptops -- it might not turn off your
2821	  backlight at all, or it might print a lot of errors to the console,
2822	  especially if you are using gpm.
2823
2824config APM_ALLOW_INTS
2825	bool "Allow interrupts during APM BIOS calls"
2826	help
2827	  Normally we disable external interrupts while we are making calls to
2828	  the APM BIOS as a measure to lessen the effects of a badly behaving
2829	  BIOS implementation.  The BIOS should reenable interrupts if it
2830	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2831	  many of the newer IBM Thinkpads.  If you experience hangs when you
2832	  suspend, try setting this to Y.  Otherwise, say N.
2833
2834endif # APM
2835
2836source "drivers/cpufreq/Kconfig"
2837
2838source "drivers/cpuidle/Kconfig"
2839
2840source "drivers/idle/Kconfig"
2841
2842endmenu
2843
2844menu "Bus options (PCI etc.)"
2845
2846choice
2847	prompt "PCI access mode"
2848	depends on X86_32 && PCI
2849	default PCI_GOANY
2850	help
2851	  On PCI systems, the BIOS can be used to detect the PCI devices and
2852	  determine their configuration. However, some old PCI motherboards
2853	  have BIOS bugs and may crash if this is done. Also, some embedded
2854	  PCI-based systems don't have any BIOS at all. Linux can also try to
2855	  detect the PCI hardware directly without using the BIOS.
2856
2857	  With this option, you can specify how Linux should detect the
2858	  PCI devices. If you choose "BIOS", the BIOS will be used,
2859	  if you choose "Direct", the BIOS won't be used, and if you
2860	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2861	  If you choose "Any", the kernel will try MMCONFIG, then the
2862	  direct access method and falls back to the BIOS if that doesn't
2863	  work. If unsure, go with the default, which is "Any".
2864
2865config PCI_GOBIOS
2866	bool "BIOS"
2867
2868config PCI_GOMMCONFIG
2869	bool "MMConfig"
2870
2871config PCI_GODIRECT
2872	bool "Direct"
2873
2874config PCI_GOOLPC
2875	bool "OLPC XO-1"
2876	depends on OLPC
2877
2878config PCI_GOANY
2879	bool "Any"
2880
2881endchoice
2882
2883config PCI_BIOS
2884	def_bool y
2885	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2886
2887# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2888config PCI_DIRECT
2889	def_bool y
2890	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2891
2892config PCI_MMCONFIG
2893	bool "Support mmconfig PCI config space access" if X86_64
2894	default y
2895	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2896	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2897	help
2898	  Add support for accessing the PCI configuration space as a memory
2899	  mapped area. It is the recommended method if the system supports
2900	  this (it must have PCI Express and ACPI for it to be available).
2901
2902	  In the unlikely case that enabling this configuration option causes
2903	  problems, the mechanism can be switched off with the 'pci=nommconf'
2904	  command line parameter.
2905
2906	  Say N only if you are sure that your platform does not support this
2907	  access method or you have problems caused by it.
2908
2909	  Say Y otherwise.
2910
2911config PCI_OLPC
2912	def_bool y
2913	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2914
2915config PCI_XEN
2916	def_bool y
2917	depends on PCI && XEN
2918
2919config MMCONF_FAM10H
2920	def_bool y
2921	depends on X86_64 && PCI_MMCONFIG && ACPI
2922
2923config PCI_CNB20LE_QUIRK
2924	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2925	depends on X86_32 && PCI
2926	help
2927	  Read the PCI windows out of the CNB20LE host bridge. This allows
2928	  PCI hotplug to work on systems with the CNB20LE chipset which do
2929	  not have ACPI.
2930
2931	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2932	  most probably only for Pentium III.
2933
2934	  To find out if you have such a chipset, search for a PCI device with
2935	  1166:0009 PCI IDs, for example by executing
2936		lspci -nn | grep '1166:0009'
2937	  The code is inactive if there is none.
2938
2939	  There's no public spec for this chipset, and this functionality
2940	  is known to be incomplete.
2941
2942	  You should say N unless you know you need this.
2943
2944config ISA_BUS
2945	bool "ISA bus support on modern systems" if EXPERT
2946	help
2947	  Expose ISA bus device drivers and options available for selection and
2948	  configuration. Enable this option if your target machine has an ISA
2949	  bus. ISA is an older system, displaced by PCI and newer bus
2950	  architectures -- if your target machine is modern, it probably does
2951	  not have an ISA bus.
2952
2953	  If unsure, say N.
2954
2955# x86_64 have no ISA slots, but can have ISA-style DMA.
2956config ISA_DMA_API
2957	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2958	default y
2959	help
2960	  Enables ISA-style DMA support for devices requiring such controllers.
2961	  If unsure, say Y.
2962
2963if X86_32
2964
2965config ISA
2966	bool "ISA support"
2967	help
2968	  Find out whether you have ISA slots on your motherboard.  ISA is the
2969	  name of a bus system, i.e. the way the CPU talks to the other stuff
2970	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2971	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2972	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2973
2974config SCx200
2975	tristate "NatSemi SCx200 support"
2976	help
2977	  This provides basic support for National Semiconductor's
2978	  (now AMD's) Geode processors.  The driver probes for the
2979	  PCI-IDs of several on-chip devices, so its a good dependency
2980	  for other scx200_* drivers.
2981
2982	  If compiled as a module, the driver is named scx200.
2983
2984config SCx200HR_TIMER
2985	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2986	depends on SCx200
2987	default y
2988	help
2989	  This driver provides a clocksource built upon the on-chip
2990	  27MHz high-resolution timer.  Its also a workaround for
2991	  NSC Geode SC-1100's buggy TSC, which loses time when the
2992	  processor goes idle (as is done by the scheduler).  The
2993	  other workaround is idle=poll boot option.
2994
2995config OLPC
2996	bool "One Laptop Per Child support"
2997	depends on !X86_PAE
2998	select GPIOLIB
2999	select OF
3000	select OF_PROMTREE
3001	select IRQ_DOMAIN
3002	select OLPC_EC
3003	help
3004	  Add support for detecting the unique features of the OLPC
3005	  XO hardware.
3006
3007config OLPC_XO1_PM
3008	bool "OLPC XO-1 Power Management"
3009	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3010	help
3011	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3012
3013config OLPC_XO1_RTC
3014	bool "OLPC XO-1 Real Time Clock"
3015	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3016	help
3017	  Add support for the XO-1 real time clock, which can be used as a
3018	  programmable wakeup source.
3019
3020config OLPC_XO1_SCI
3021	bool "OLPC XO-1 SCI extras"
3022	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3023	depends on INPUT=y
3024	select POWER_SUPPLY
3025	help
3026	  Add support for SCI-based features of the OLPC XO-1 laptop:
3027	   - EC-driven system wakeups
3028	   - Power button
3029	   - Ebook switch
3030	   - Lid switch
3031	   - AC adapter status updates
3032	   - Battery status updates
3033
3034config OLPC_XO15_SCI
3035	bool "OLPC XO-1.5 SCI extras"
3036	depends on OLPC && ACPI
3037	select POWER_SUPPLY
3038	help
3039	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3040	   - EC-driven system wakeups
3041	   - AC adapter status updates
3042	   - Battery status updates
3043
3044config GEODE_COMMON
3045	bool
3046
3047config ALIX
3048	bool "PCEngines ALIX System Support (LED setup)"
3049	select GPIOLIB
3050	select GEODE_COMMON
3051	help
3052	  This option enables system support for the PCEngines ALIX.
3053	  At present this just sets up LEDs for GPIO control on
3054	  ALIX2/3/6 boards.  However, other system specific setup should
3055	  get added here.
3056
3057	  Note: You must still enable the drivers for GPIO and LED support
3058	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3059
3060	  Note: You have to set alix.force=1 for boards with Award BIOS.
3061
3062config NET5501
3063	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3064	select GPIOLIB
3065	select GEODE_COMMON
3066	help
3067	  This option enables system support for the Soekris Engineering net5501.
3068
3069config GEOS
3070	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3071	select GPIOLIB
3072	select GEODE_COMMON
3073	depends on DMI
3074	help
3075	  This option enables system support for the Traverse Technologies GEOS.
3076
3077config TS5500
3078	bool "Technologic Systems TS-5500 platform support"
3079	depends on MELAN
3080	select CHECK_SIGNATURE
3081	select NEW_LEDS
3082	select LEDS_CLASS
3083	help
3084	  This option enables system support for the Technologic Systems TS-5500.
3085
3086endif # X86_32
3087
3088config AMD_NB
3089	def_bool y
3090	depends on AMD_NODE
3091
3092config AMD_NODE
3093	def_bool y
3094	depends on CPU_SUP_AMD && PCI
3095
3096endmenu
3097
3098menu "Binary Emulations"
3099
3100config IA32_EMULATION
3101	bool "IA32 Emulation"
3102	depends on X86_64
3103	select ARCH_WANT_OLD_COMPAT_IPC
3104	select BINFMT_ELF
3105	select COMPAT_OLD_SIGACTION
3106	help
3107	  Include code to run legacy 32-bit programs under a
3108	  64-bit kernel. You should likely turn this on, unless you're
3109	  100% sure that you don't have any 32-bit programs left.
3110
3111config IA32_EMULATION_DEFAULT_DISABLED
3112	bool "IA32 emulation disabled by default"
3113	default n
3114	depends on IA32_EMULATION
3115	help
3116	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3117	  processes and access to 32-bit syscalls. If unsure, leave it to its
3118	  default value.
3119
3120config X86_X32_ABI
3121	bool "x32 ABI for 64-bit mode"
3122	depends on X86_64
3123	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3124	# compressed debug sections to x86_x32 properly:
3125	# https://github.com/ClangBuiltLinux/linux/issues/514
3126	# https://github.com/ClangBuiltLinux/linux/issues/1141
3127	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3128	help
3129	  Include code to run binaries for the x32 native 32-bit ABI
3130	  for 64-bit processors.  An x32 process gets access to the
3131	  full 64-bit register file and wide data path while leaving
3132	  pointers at 32 bits for smaller memory footprint.
3133
3134config COMPAT_32
3135	def_bool y
3136	depends on IA32_EMULATION || X86_32
3137	select HAVE_UID16
3138	select OLD_SIGSUSPEND3
3139
3140config COMPAT
3141	def_bool y
3142	depends on IA32_EMULATION || X86_X32_ABI
3143
3144config COMPAT_FOR_U64_ALIGNMENT
3145	def_bool y
3146	depends on COMPAT
3147
3148endmenu
3149
3150config HAVE_ATOMIC_IOMAP
3151	def_bool y
3152	depends on X86_32
3153
3154source "arch/x86/kvm/Kconfig"
3155
3156source "arch/x86/Kconfig.cpufeatures"
3157
3158source "arch/x86/Kconfig.assembler"
3159