xref: /linux/arch/x86/Kconfig (revision a58f3dcf20ea9e7e968ee8369fd782bbb53dff73)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select GENERIC_VDSO_32
18	select HAVE_DEBUG_STACKOVERFLOW
19	select KMAP_LOCAL
20	select MODULES_USE_ELF_REL
21	select OLD_SIGACTION
22	select ARCH_SPLIT_ARG64
23
24config X86_64
25	def_bool y
26	depends on 64BIT
27	# Options that are inherently 64-bit kernel only:
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_SUPPORTS_PER_VMA_LOCK
31	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
32	select HAVE_ARCH_SOFT_DIRTY
33	select MODULES_USE_ELF_RELA
34	select NEED_DMA_MAP_STATE
35	select SWIOTLB
36	select ARCH_HAS_ELFCORE_COMPAT
37	select ZONE_DMA32
38	select EXECMEM if DYNAMIC_FTRACE
39
40config FORCE_DYNAMIC_FTRACE
41	def_bool y
42	depends on X86_32
43	depends on FUNCTION_TRACER
44	select DYNAMIC_FTRACE
45	help
46	  We keep the static function tracing (!DYNAMIC_FTRACE) around
47	  in order to test the non static function tracing in the
48	  generic code, as other architectures still use it. But we
49	  only need to keep it around for x86_64. No need to keep it
50	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
51#
52# Arch settings
53#
54# ( Note that options that are marked 'if X86_64' could in principle be
55#   ported to 32-bit as well. )
56#
57config X86
58	def_bool y
59	#
60	# Note: keep this list sorted alphabetically
61	#
62	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
63	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
64	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
65	select ARCH_32BIT_OFF_T			if X86_32
66	select ARCH_CLOCKSOURCE_INIT
67	select ARCH_CONFIGURES_CPU_MITIGATIONS
68	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
69	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
70	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
71	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
72	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
73	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
74	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
75	select ARCH_HAS_CACHE_LINE_SIZE
76	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
77	select ARCH_HAS_CPU_FINALIZE_INIT
78	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
79	select ARCH_HAS_CRC32
80	select ARCH_HAS_CRC_T10DIF		if X86_64
81	select ARCH_HAS_CURRENT_STACK_POINTER
82	select ARCH_HAS_DEBUG_VIRTUAL
83	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
84	select ARCH_HAS_DEVMEM_IS_ALLOWED
85	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
86	select ARCH_HAS_EARLY_DEBUG		if KGDB
87	select ARCH_HAS_ELF_RANDOMIZE
88	select ARCH_HAS_FAST_MULTIPLIER
89	select ARCH_HAS_FORTIFY_SOURCE
90	select ARCH_HAS_GCOV_PROFILE_ALL
91	select ARCH_HAS_KCOV			if X86_64
92	select ARCH_HAS_KERNEL_FPU_SUPPORT
93	select ARCH_HAS_MEM_ENCRYPT
94	select ARCH_HAS_MEMBARRIER_SYNC_CORE
95	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
96	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
97	select ARCH_HAS_PMEM_API		if X86_64
98	select ARCH_HAS_PREEMPT_LAZY
99	select ARCH_HAS_PTE_DEVMAP		if X86_64
100	select ARCH_HAS_PTE_SPECIAL
101	select ARCH_HAS_HW_PTE_YOUNG
102	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
103	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
104	select ARCH_HAS_COPY_MC			if X86_64
105	select ARCH_HAS_SET_MEMORY
106	select ARCH_HAS_SET_DIRECT_MAP
107	select ARCH_HAS_STRICT_KERNEL_RWX
108	select ARCH_HAS_STRICT_MODULE_RWX
109	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
110	select ARCH_HAS_SYSCALL_WRAPPER
111	select ARCH_HAS_UBSAN
112	select ARCH_HAS_DEBUG_WX
113	select ARCH_HAS_ZONE_DMA_SET if EXPERT
114	select ARCH_HAVE_NMI_SAFE_CMPXCHG
115	select ARCH_HAVE_EXTRA_ELF_NOTES
116	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
117	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
118	select ARCH_MIGHT_HAVE_PC_PARPORT
119	select ARCH_MIGHT_HAVE_PC_SERIO
120	select ARCH_STACKWALK
121	select ARCH_SUPPORTS_ACPI
122	select ARCH_SUPPORTS_ATOMIC_RMW
123	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
124	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
125	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
126	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
127	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
128	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
129	select ARCH_SUPPORTS_LTO_CLANG
130	select ARCH_SUPPORTS_LTO_CLANG_THIN
131	select ARCH_SUPPORTS_RT
132	select ARCH_SUPPORTS_AUTOFDO_CLANG
133	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
134	select ARCH_USE_BUILTIN_BSWAP
135	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CMPXCHG64
136	select ARCH_USE_MEMTEST
137	select ARCH_USE_QUEUED_RWLOCKS
138	select ARCH_USE_QUEUED_SPINLOCKS
139	select ARCH_USE_SYM_ANNOTATIONS
140	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
141	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
142	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
143	select ARCH_WANTS_NO_INSTR
144	select ARCH_WANT_GENERAL_HUGETLB
145	select ARCH_WANT_HUGE_PMD_SHARE
146	select ARCH_WANT_LD_ORPHAN_WARN
147	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
148	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
149	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
150	select ARCH_WANTS_THP_SWAP		if X86_64
151	select ARCH_HAS_PARANOID_L1D_FLUSH
152	select BUILDTIME_TABLE_SORT
153	select CLKEVT_I8253
154	select CLOCKSOURCE_WATCHDOG
155	# Word-size accesses may read uninitialized data past the trailing \0
156	# in strings and cause false KMSAN reports.
157	select DCACHE_WORD_ACCESS		if !KMSAN
158	select DYNAMIC_SIGFRAME
159	select EDAC_ATOMIC_SCRUB
160	select EDAC_SUPPORT
161	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
162	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
163	select GENERIC_CLOCKEVENTS_MIN_ADJUST
164	select GENERIC_CMOS_UPDATE
165	select GENERIC_CPU_AUTOPROBE
166	select GENERIC_CPU_DEVICES
167	select GENERIC_CPU_VULNERABILITIES
168	select GENERIC_EARLY_IOREMAP
169	select GENERIC_ENTRY
170	select GENERIC_IOMAP
171	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
172	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
173	select GENERIC_IRQ_MIGRATION		if SMP
174	select GENERIC_IRQ_PROBE
175	select GENERIC_IRQ_RESERVATION_MODE
176	select GENERIC_IRQ_SHOW
177	select GENERIC_PENDING_IRQ		if SMP
178	select GENERIC_PTDUMP
179	select GENERIC_SMP_IDLE_THREAD
180	select GENERIC_TIME_VSYSCALL
181	select GENERIC_GETTIMEOFDAY
182	select GENERIC_VDSO_TIME_NS
183	select GENERIC_VDSO_OVERFLOW_PROTECT
184	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
185	select HARDIRQS_SW_RESEND
186	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
187	select HAS_IOPORT
188	select HAVE_ACPI_APEI			if ACPI
189	select HAVE_ACPI_APEI_NMI		if ACPI
190	select HAVE_ALIGNED_STRUCT_PAGE
191	select HAVE_ARCH_AUDITSYSCALL
192	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
193	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
194	select HAVE_ARCH_JUMP_LABEL
195	select HAVE_ARCH_JUMP_LABEL_RELATIVE
196	select HAVE_ARCH_KASAN			if X86_64
197	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
198	select HAVE_ARCH_KFENCE
199	select HAVE_ARCH_KMSAN			if X86_64
200	select HAVE_ARCH_KGDB
201	select HAVE_ARCH_MMAP_RND_BITS		if MMU
202	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
203	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
204	select HAVE_ARCH_PREL32_RELOCATIONS
205	select HAVE_ARCH_SECCOMP_FILTER
206	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
207	select HAVE_ARCH_STACKLEAK
208	select HAVE_ARCH_TRACEHOOK
209	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
210	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
211	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
212	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
213	select HAVE_ARCH_VMAP_STACK		if X86_64
214	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
215	select HAVE_ARCH_WITHIN_STACK_FRAMES
216	select HAVE_ASM_MODVERSIONS
217	select HAVE_CMPXCHG_DOUBLE
218	select HAVE_CMPXCHG_LOCAL
219	select HAVE_CONTEXT_TRACKING_USER		if X86_64
220	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
221	select HAVE_C_RECORDMCOUNT
222	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
223	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
224	select HAVE_BUILDTIME_MCOUNT_SORT
225	select HAVE_DEBUG_KMEMLEAK
226	select HAVE_DMA_CONTIGUOUS
227	select HAVE_DYNAMIC_FTRACE
228	select HAVE_DYNAMIC_FTRACE_WITH_REGS
229	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
230	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
231	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
232	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
233	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
234	select HAVE_EBPF_JIT
235	select HAVE_EFFICIENT_UNALIGNED_ACCESS
236	select HAVE_EISA
237	select HAVE_EXIT_THREAD
238	select HAVE_GUP_FAST
239	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
240	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
241	select HAVE_FTRACE_MCOUNT_RECORD
242	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
243	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
244	select HAVE_FUNCTION_TRACER
245	select HAVE_GCC_PLUGINS
246	select HAVE_HW_BREAKPOINT
247	select HAVE_IOREMAP_PROT
248	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
249	select HAVE_IRQ_TIME_ACCOUNTING
250	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
251	select HAVE_KERNEL_BZIP2
252	select HAVE_KERNEL_GZIP
253	select HAVE_KERNEL_LZ4
254	select HAVE_KERNEL_LZMA
255	select HAVE_KERNEL_LZO
256	select HAVE_KERNEL_XZ
257	select HAVE_KERNEL_ZSTD
258	select HAVE_KPROBES
259	select HAVE_KPROBES_ON_FTRACE
260	select HAVE_FUNCTION_ERROR_INJECTION
261	select HAVE_KRETPROBES
262	select HAVE_RETHOOK
263	select HAVE_LIVEPATCH			if X86_64
264	select HAVE_MIXED_BREAKPOINTS_REGS
265	select HAVE_MOD_ARCH_SPECIFIC
266	select HAVE_MOVE_PMD
267	select HAVE_MOVE_PUD
268	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
269	select HAVE_NMI
270	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
271	select HAVE_OBJTOOL			if X86_64
272	select HAVE_OPTPROBES
273	select HAVE_PAGE_SIZE_4KB
274	select HAVE_PCSPKR_PLATFORM
275	select HAVE_PERF_EVENTS
276	select HAVE_PERF_EVENTS_NMI
277	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
278	select HAVE_PCI
279	select HAVE_PERF_REGS
280	select HAVE_PERF_USER_STACK_DUMP
281	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
282	select MMU_GATHER_MERGE_VMAS
283	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
284	select HAVE_REGS_AND_STACK_ACCESS_API
285	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
286	select HAVE_FUNCTION_ARG_ACCESS_API
287	select HAVE_SETUP_PER_CPU_AREA
288	select HAVE_SOFTIRQ_ON_OWN_STACK
289	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
290	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
291	select HAVE_STATIC_CALL
292	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
293	select HAVE_PREEMPT_DYNAMIC_CALL
294	select HAVE_RSEQ
295	select HAVE_RUST			if X86_64
296	select HAVE_SYSCALL_TRACEPOINTS
297	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
298	select HAVE_UNSTABLE_SCHED_CLOCK
299	select HAVE_USER_RETURN_NOTIFIER
300	select HAVE_GENERIC_VDSO
301	select VDSO_GETRANDOM			if X86_64
302	select HOTPLUG_PARALLEL			if SMP && X86_64
303	select HOTPLUG_SMT			if SMP
304	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
305	select IRQ_FORCED_THREADING
306	select LOCK_MM_AND_FIND_VMA
307	select NEED_PER_CPU_EMBED_FIRST_CHUNK
308	select NEED_PER_CPU_PAGE_FIRST_CHUNK
309	select NEED_SG_DMA_LENGTH
310	select NUMA_MEMBLKS			if NUMA
311	select PCI_DOMAINS			if PCI
312	select PCI_LOCKLESS_CONFIG		if PCI
313	select PERF_EVENTS
314	select RTC_LIB
315	select RTC_MC146818_LIB
316	select SPARSE_IRQ
317	select SYSCTL_EXCEPTION_TRACE
318	select THREAD_INFO_IN_TASK
319	select TRACE_IRQFLAGS_SUPPORT
320	select TRACE_IRQFLAGS_NMI_SUPPORT
321	select USER_STACKTRACE_SUPPORT
322	select HAVE_ARCH_KCSAN			if X86_64
323	select PROC_PID_ARCH_STATUS		if PROC_FS
324	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
325	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
326	select FUNCTION_ALIGNMENT_4B
327	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
328	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
329	select ARCH_SUPPORTS_PT_RECLAIM		if X86_64
330
331config INSTRUCTION_DECODER
332	def_bool y
333	depends on KPROBES || PERF_EVENTS || UPROBES
334
335config OUTPUT_FORMAT
336	string
337	default "elf32-i386" if X86_32
338	default "elf64-x86-64" if X86_64
339
340config LOCKDEP_SUPPORT
341	def_bool y
342
343config STACKTRACE_SUPPORT
344	def_bool y
345
346config MMU
347	def_bool y
348
349config ARCH_MMAP_RND_BITS_MIN
350	default 28 if 64BIT
351	default 8
352
353config ARCH_MMAP_RND_BITS_MAX
354	default 32 if 64BIT
355	default 16
356
357config ARCH_MMAP_RND_COMPAT_BITS_MIN
358	default 8
359
360config ARCH_MMAP_RND_COMPAT_BITS_MAX
361	default 16
362
363config SBUS
364	bool
365
366config GENERIC_ISA_DMA
367	def_bool y
368	depends on ISA_DMA_API
369
370config GENERIC_CSUM
371	bool
372	default y if KMSAN || KASAN
373
374config GENERIC_BUG
375	def_bool y
376	depends on BUG
377	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
378
379config GENERIC_BUG_RELATIVE_POINTERS
380	bool
381
382config ARCH_MAY_HAVE_PC_FDC
383	def_bool y
384	depends on ISA_DMA_API
385
386config GENERIC_CALIBRATE_DELAY
387	def_bool y
388
389config ARCH_HAS_CPU_RELAX
390	def_bool y
391
392config ARCH_HIBERNATION_POSSIBLE
393	def_bool y
394
395config ARCH_SUSPEND_POSSIBLE
396	def_bool y
397
398config AUDIT_ARCH
399	def_bool y if X86_64
400
401config KASAN_SHADOW_OFFSET
402	hex
403	depends on KASAN
404	default 0xdffffc0000000000
405
406config HAVE_INTEL_TXT
407	def_bool y
408	depends on INTEL_IOMMU && ACPI
409
410config X86_64_SMP
411	def_bool y
412	depends on X86_64 && SMP
413
414config ARCH_SUPPORTS_UPROBES
415	def_bool y
416
417config FIX_EARLYCON_MEM
418	def_bool y
419
420config DYNAMIC_PHYSICAL_MASK
421	bool
422
423config PGTABLE_LEVELS
424	int
425	default 5 if X86_5LEVEL
426	default 4 if X86_64
427	default 3 if X86_PAE
428	default 2
429
430config CC_HAS_SANE_STACKPROTECTOR
431	bool
432	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
433	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
434	help
435	  We have to make sure stack protector is unconditionally disabled if
436	  the compiler produces broken code or if it does not let us control
437	  the segment on 32-bit kernels.
438
439menu "Processor type and features"
440
441config SMP
442	bool "Symmetric multi-processing support"
443	help
444	  This enables support for systems with more than one CPU. If you have
445	  a system with only one CPU, say N. If you have a system with more
446	  than one CPU, say Y.
447
448	  If you say N here, the kernel will run on uni- and multiprocessor
449	  machines, but will use only one CPU of a multiprocessor machine. If
450	  you say Y here, the kernel will run on many, but not all,
451	  uniprocessor machines. On a uniprocessor machine, the kernel
452	  will run faster if you say N here.
453
454	  Note that if you say Y here and choose architecture "586" or
455	  "Pentium" under "Processor family", the kernel will not work on 486
456	  architectures. Similarly, multiprocessor kernels for the "PPro"
457	  architecture may not work on all Pentium based boards.
458
459	  People using multiprocessor machines who say Y here should also say
460	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
461	  Management" code will be disabled if you say Y here.
462
463	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
464	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
465	  <http://www.tldp.org/docs.html#howto>.
466
467	  If you don't know what to do here, say N.
468
469config X86_X2APIC
470	bool "Support x2apic"
471	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
472	help
473	  This enables x2apic support on CPUs that have this feature.
474
475	  This allows 32-bit apic IDs (so it can support very large systems),
476	  and accesses the local apic via MSRs not via mmio.
477
478	  Some Intel systems circa 2022 and later are locked into x2APIC mode
479	  and can not fall back to the legacy APIC modes if SGX or TDX are
480	  enabled in the BIOS. They will boot with very reduced functionality
481	  without enabling this option.
482
483	  If you don't know what to do here, say N.
484
485config X86_POSTED_MSI
486	bool "Enable MSI and MSI-x delivery by posted interrupts"
487	depends on X86_64 && IRQ_REMAP
488	help
489	  This enables MSIs that are under interrupt remapping to be delivered as
490	  posted interrupts to the host kernel. Interrupt throughput can
491	  potentially be improved by coalescing CPU notifications during high
492	  frequency bursts.
493
494	  If you don't know what to do here, say N.
495
496config X86_MPPARSE
497	bool "Enable MPS table" if ACPI
498	default y
499	depends on X86_LOCAL_APIC
500	help
501	  For old smp systems that do not have proper acpi support. Newer systems
502	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
503
504config X86_CPU_RESCTRL
505	bool "x86 CPU resource control support"
506	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
507	select KERNFS
508	select PROC_CPU_RESCTRL		if PROC_FS
509	help
510	  Enable x86 CPU resource control support.
511
512	  Provide support for the allocation and monitoring of system resources
513	  usage by the CPU.
514
515	  Intel calls this Intel Resource Director Technology
516	  (Intel(R) RDT). More information about RDT can be found in the
517	  Intel x86 Architecture Software Developer Manual.
518
519	  AMD calls this AMD Platform Quality of Service (AMD QoS).
520	  More information about AMD QoS can be found in the AMD64 Technology
521	  Platform Quality of Service Extensions manual.
522
523	  Say N if unsure.
524
525config X86_FRED
526	bool "Flexible Return and Event Delivery"
527	depends on X86_64
528	help
529	  When enabled, try to use Flexible Return and Event Delivery
530	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
531	  ring transitions and exception/interrupt handling if the
532	  system supports it.
533
534config X86_BIGSMP
535	bool "Support for big SMP systems with more than 8 CPUs"
536	depends on SMP && X86_32
537	help
538	  This option is needed for the systems that have more than 8 CPUs.
539
540config X86_EXTENDED_PLATFORM
541	bool "Support for extended (non-PC) x86 platforms"
542	default y
543	help
544	  If you disable this option then the kernel will only support
545	  standard PC platforms. (which covers the vast majority of
546	  systems out there.)
547
548	  If you enable this option then you'll be able to select support
549	  for the following non-PC x86 platforms, depending on the value of
550	  CONFIG_64BIT.
551
552	  32-bit platforms (CONFIG_64BIT=n):
553		Goldfish (Android emulator)
554		AMD Elan
555		RDC R-321x SoC
556		SGI 320/540 (Visual Workstation)
557		STA2X11-based (e.g. Northville)
558		Moorestown MID devices
559
560	  64-bit platforms (CONFIG_64BIT=y):
561		Numascale NumaChip
562		ScaleMP vSMP
563		SGI Ultraviolet
564
565	  If you have one of these systems, or if you want to build a
566	  generic distribution kernel, say Y here - otherwise say N.
567
568# This is an alphabetically sorted list of 64 bit extended platforms
569# Please maintain the alphabetic order if and when there are additions
570config X86_NUMACHIP
571	bool "Numascale NumaChip"
572	depends on X86_64
573	depends on X86_EXTENDED_PLATFORM
574	depends on NUMA
575	depends on SMP
576	depends on X86_X2APIC
577	depends on PCI_MMCONFIG
578	help
579	  Adds support for Numascale NumaChip large-SMP systems. Needed to
580	  enable more than ~168 cores.
581	  If you don't have one of these, you should say N here.
582
583config X86_VSMP
584	bool "ScaleMP vSMP"
585	select HYPERVISOR_GUEST
586	select PARAVIRT
587	depends on X86_64 && PCI
588	depends on X86_EXTENDED_PLATFORM
589	depends on SMP
590	help
591	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
592	  supposed to run on these EM64T-based machines.  Only choose this option
593	  if you have one of these machines.
594
595config X86_UV
596	bool "SGI Ultraviolet"
597	depends on X86_64
598	depends on X86_EXTENDED_PLATFORM
599	depends on NUMA
600	depends on EFI
601	depends on KEXEC_CORE
602	depends on X86_X2APIC
603	depends on PCI
604	help
605	  This option is needed in order to support SGI Ultraviolet systems.
606	  If you don't have one of these, you should say N here.
607
608# Following is an alphabetically sorted list of 32 bit extended platforms
609# Please maintain the alphabetic order if and when there are additions
610
611config X86_GOLDFISH
612	bool "Goldfish (Virtual Platform)"
613	depends on X86_EXTENDED_PLATFORM
614	help
615	  Enable support for the Goldfish virtual platform used primarily
616	  for Android development. Unless you are building for the Android
617	  Goldfish emulator say N here.
618
619config X86_INTEL_CE
620	bool "CE4100 TV platform"
621	depends on PCI
622	depends on PCI_GODIRECT
623	depends on X86_IO_APIC
624	depends on X86_32
625	depends on X86_EXTENDED_PLATFORM
626	select X86_REBOOTFIXUPS
627	select OF
628	select OF_EARLY_FLATTREE
629	help
630	  Select for the Intel CE media processor (CE4100) SOC.
631	  This option compiles in support for the CE4100 SOC for settop
632	  boxes and media devices.
633
634config X86_INTEL_MID
635	bool "Intel MID platform support"
636	depends on X86_EXTENDED_PLATFORM
637	depends on X86_PLATFORM_DEVICES
638	depends on PCI
639	depends on X86_64 || (PCI_GOANY && X86_32)
640	depends on X86_IO_APIC
641	select I2C
642	select DW_APB_TIMER
643	select INTEL_SCU_PCI
644	help
645	  Select to build a kernel capable of supporting Intel MID (Mobile
646	  Internet Device) platform systems which do not have the PCI legacy
647	  interfaces. If you are building for a PC class system say N here.
648
649	  Intel MID platforms are based on an Intel processor and chipset which
650	  consume less power than most of the x86 derivatives.
651
652config X86_INTEL_QUARK
653	bool "Intel Quark platform support"
654	depends on X86_32
655	depends on X86_EXTENDED_PLATFORM
656	depends on X86_PLATFORM_DEVICES
657	depends on X86_TSC
658	depends on PCI
659	depends on PCI_GOANY
660	depends on X86_IO_APIC
661	select IOSF_MBI
662	select INTEL_IMR
663	select COMMON_CLK
664	help
665	  Select to include support for Quark X1000 SoC.
666	  Say Y here if you have a Quark based system such as the Arduino
667	  compatible Intel Galileo.
668
669config X86_INTEL_LPSS
670	bool "Intel Low Power Subsystem Support"
671	depends on X86 && ACPI && PCI
672	select COMMON_CLK
673	select PINCTRL
674	select IOSF_MBI
675	help
676	  Select to build support for Intel Low Power Subsystem such as
677	  found on Intel Lynxpoint PCH. Selecting this option enables
678	  things like clock tree (common clock framework) and pincontrol
679	  which are needed by the LPSS peripheral drivers.
680
681config X86_AMD_PLATFORM_DEVICE
682	bool "AMD ACPI2Platform devices support"
683	depends on ACPI
684	select COMMON_CLK
685	select PINCTRL
686	help
687	  Select to interpret AMD specific ACPI device to platform device
688	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
689	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
690	  implemented under PINCTRL subsystem.
691
692config IOSF_MBI
693	tristate "Intel SoC IOSF Sideband support for SoC platforms"
694	depends on PCI
695	help
696	  This option enables sideband register access support for Intel SoC
697	  platforms. On these platforms the IOSF sideband is used in lieu of
698	  MSR's for some register accesses, mostly but not limited to thermal
699	  and power. Drivers may query the availability of this device to
700	  determine if they need the sideband in order to work on these
701	  platforms. The sideband is available on the following SoC products.
702	  This list is not meant to be exclusive.
703	   - BayTrail
704	   - Braswell
705	   - Quark
706
707	  You should say Y if you are running a kernel on one of these SoC's.
708
709config IOSF_MBI_DEBUG
710	bool "Enable IOSF sideband access through debugfs"
711	depends on IOSF_MBI && DEBUG_FS
712	help
713	  Select this option to expose the IOSF sideband access registers (MCR,
714	  MDR, MCRX) through debugfs to write and read register information from
715	  different units on the SoC. This is most useful for obtaining device
716	  state information for debug and analysis. As this is a general access
717	  mechanism, users of this option would have specific knowledge of the
718	  device they want to access.
719
720	  If you don't require the option or are in doubt, say N.
721
722config X86_RDC321X
723	bool "RDC R-321x SoC"
724	depends on X86_32
725	depends on X86_EXTENDED_PLATFORM
726	select M486
727	select X86_REBOOTFIXUPS
728	help
729	  This option is needed for RDC R-321x system-on-chip, also known
730	  as R-8610-(G).
731	  If you don't have one of these chips, you should say N here.
732
733config X86_32_NON_STANDARD
734	bool "Support non-standard 32-bit SMP architectures"
735	depends on X86_32 && SMP
736	depends on X86_EXTENDED_PLATFORM
737	help
738	  This option compiles in the bigsmp and STA2X11 default
739	  subarchitectures.  It is intended for a generic binary
740	  kernel. If you select them all, kernel will probe it one by
741	  one and will fallback to default.
742
743# Alphabetically sorted list of Non standard 32 bit platforms
744
745config X86_SUPPORTS_MEMORY_FAILURE
746	def_bool y
747	# MCE code calls memory_failure():
748	depends on X86_MCE
749	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
750	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
751	depends on X86_64 || !SPARSEMEM
752	select ARCH_SUPPORTS_MEMORY_FAILURE
753
754config STA2X11
755	bool "STA2X11 Companion Chip Support"
756	depends on X86_32_NON_STANDARD && PCI
757	select SWIOTLB
758	select MFD_STA2X11
759	select GPIOLIB
760	help
761	  This adds support for boards based on the STA2X11 IO-Hub,
762	  a.k.a. "ConneXt". The chip is used in place of the standard
763	  PC chipset, so all "standard" peripherals are missing. If this
764	  option is selected the kernel will still be able to boot on
765	  standard PC machines.
766
767config X86_32_IRIS
768	tristate "Eurobraille/Iris poweroff module"
769	depends on X86_32
770	help
771	  The Iris machines from EuroBraille do not have APM or ACPI support
772	  to shut themselves down properly.  A special I/O sequence is
773	  needed to do so, which is what this module does at
774	  kernel shutdown.
775
776	  This is only for Iris machines from EuroBraille.
777
778	  If unused, say N.
779
780config SCHED_OMIT_FRAME_POINTER
781	def_bool y
782	prompt "Single-depth WCHAN output"
783	depends on X86
784	help
785	  Calculate simpler /proc/<PID>/wchan values. If this option
786	  is disabled then wchan values will recurse back to the
787	  caller function. This provides more accurate wchan values,
788	  at the expense of slightly more scheduling overhead.
789
790	  If in doubt, say "Y".
791
792menuconfig HYPERVISOR_GUEST
793	bool "Linux guest support"
794	help
795	  Say Y here to enable options for running Linux under various hyper-
796	  visors. This option enables basic hypervisor detection and platform
797	  setup.
798
799	  If you say N, all options in this submenu will be skipped and
800	  disabled, and Linux guest support won't be built in.
801
802if HYPERVISOR_GUEST
803
804config PARAVIRT
805	bool "Enable paravirtualization code"
806	depends on HAVE_STATIC_CALL
807	help
808	  This changes the kernel so it can modify itself when it is run
809	  under a hypervisor, potentially improving performance significantly
810	  over full virtualization.  However, when run without a hypervisor
811	  the kernel is theoretically slower and slightly larger.
812
813config PARAVIRT_XXL
814	bool
815
816config PARAVIRT_DEBUG
817	bool "paravirt-ops debugging"
818	depends on PARAVIRT && DEBUG_KERNEL
819	help
820	  Enable to debug paravirt_ops internals.  Specifically, BUG if
821	  a paravirt_op is missing when it is called.
822
823config PARAVIRT_SPINLOCKS
824	bool "Paravirtualization layer for spinlocks"
825	depends on PARAVIRT && SMP
826	help
827	  Paravirtualized spinlocks allow a pvops backend to replace the
828	  spinlock implementation with something virtualization-friendly
829	  (for example, block the virtual CPU rather than spinning).
830
831	  It has a minimal impact on native kernels and gives a nice performance
832	  benefit on paravirtualized KVM / Xen kernels.
833
834	  If you are unsure how to answer this question, answer Y.
835
836config X86_HV_CALLBACK_VECTOR
837	def_bool n
838
839source "arch/x86/xen/Kconfig"
840
841config KVM_GUEST
842	bool "KVM Guest support (including kvmclock)"
843	depends on PARAVIRT
844	select PARAVIRT_CLOCK
845	select ARCH_CPUIDLE_HALTPOLL
846	select X86_HV_CALLBACK_VECTOR
847	default y
848	help
849	  This option enables various optimizations for running under the KVM
850	  hypervisor. It includes a paravirtualized clock, so that instead
851	  of relying on a PIT (or probably other) emulation by the
852	  underlying device model, the host provides the guest with
853	  timing infrastructure such as time of day, and system time
854
855config ARCH_CPUIDLE_HALTPOLL
856	def_bool n
857	prompt "Disable host haltpoll when loading haltpoll driver"
858	help
859	  If virtualized under KVM, disable host haltpoll.
860
861config PVH
862	bool "Support for running PVH guests"
863	help
864	  This option enables the PVH entry point for guest virtual machines
865	  as specified in the x86/HVM direct boot ABI.
866
867config PARAVIRT_TIME_ACCOUNTING
868	bool "Paravirtual steal time accounting"
869	depends on PARAVIRT
870	help
871	  Select this option to enable fine granularity task steal time
872	  accounting. Time spent executing other tasks in parallel with
873	  the current vCPU is discounted from the vCPU power. To account for
874	  that, there can be a small performance impact.
875
876	  If in doubt, say N here.
877
878config PARAVIRT_CLOCK
879	bool
880
881config JAILHOUSE_GUEST
882	bool "Jailhouse non-root cell support"
883	depends on X86_64 && PCI
884	select X86_PM_TIMER
885	help
886	  This option allows to run Linux as guest in a Jailhouse non-root
887	  cell. You can leave this option disabled if you only want to start
888	  Jailhouse and run Linux afterwards in the root cell.
889
890config ACRN_GUEST
891	bool "ACRN Guest support"
892	depends on X86_64
893	select X86_HV_CALLBACK_VECTOR
894	help
895	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
896	  a flexible, lightweight reference open-source hypervisor, built with
897	  real-time and safety-criticality in mind. It is built for embedded
898	  IOT with small footprint and real-time features. More details can be
899	  found in https://projectacrn.org/.
900
901config INTEL_TDX_GUEST
902	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
903	depends on X86_64 && CPU_SUP_INTEL
904	depends on X86_X2APIC
905	depends on EFI_STUB
906	select ARCH_HAS_CC_PLATFORM
907	select X86_MEM_ENCRYPT
908	select X86_MCE
909	select UNACCEPTED_MEMORY
910	help
911	  Support running as a guest under Intel TDX.  Without this support,
912	  the guest kernel can not boot or run under TDX.
913	  TDX includes memory encryption and integrity capabilities
914	  which protect the confidentiality and integrity of guest
915	  memory contents and CPU state. TDX guests are protected from
916	  some attacks from the VMM.
917
918endif # HYPERVISOR_GUEST
919
920source "arch/x86/Kconfig.cpu"
921
922config HPET_TIMER
923	def_bool X86_64
924	prompt "HPET Timer Support" if X86_32
925	help
926	  Use the IA-PC HPET (High Precision Event Timer) to manage
927	  time in preference to the PIT and RTC, if a HPET is
928	  present.
929	  HPET is the next generation timer replacing legacy 8254s.
930	  The HPET provides a stable time base on SMP
931	  systems, unlike the TSC, but it is more expensive to access,
932	  as it is off-chip.  The interface used is documented
933	  in the HPET spec, revision 1.
934
935	  You can safely choose Y here.  However, HPET will only be
936	  activated if the platform and the BIOS support this feature.
937	  Otherwise the 8254 will be used for timing services.
938
939	  Choose N to continue using the legacy 8254 timer.
940
941config HPET_EMULATE_RTC
942	def_bool y
943	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
944
945# Mark as expert because too many people got it wrong.
946# The code disables itself when not needed.
947config DMI
948	default y
949	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
950	bool "Enable DMI scanning" if EXPERT
951	help
952	  Enabled scanning of DMI to identify machine quirks. Say Y
953	  here unless you have verified that your setup is not
954	  affected by entries in the DMI blacklist. Required by PNP
955	  BIOS code.
956
957config GART_IOMMU
958	bool "Old AMD GART IOMMU support"
959	select IOMMU_HELPER
960	select SWIOTLB
961	depends on X86_64 && PCI && AMD_NB
962	help
963	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
964	  GART based hardware IOMMUs.
965
966	  The GART supports full DMA access for devices with 32-bit access
967	  limitations, on systems with more than 3 GB. This is usually needed
968	  for USB, sound, many IDE/SATA chipsets and some other devices.
969
970	  Newer systems typically have a modern AMD IOMMU, supported via
971	  the CONFIG_AMD_IOMMU=y config option.
972
973	  In normal configurations this driver is only active when needed:
974	  there's more than 3 GB of memory and the system contains a
975	  32-bit limited device.
976
977	  If unsure, say Y.
978
979config BOOT_VESA_SUPPORT
980	bool
981	help
982	  If true, at least one selected framebuffer driver can take advantage
983	  of VESA video modes set at an early boot stage via the vga= parameter.
984
985config MAXSMP
986	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
987	depends on X86_64 && SMP && DEBUG_KERNEL
988	select CPUMASK_OFFSTACK
989	help
990	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
991	  If unsure, say N.
992
993#
994# The maximum number of CPUs supported:
995#
996# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
997# and which can be configured interactively in the
998# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
999#
1000# The ranges are different on 32-bit and 64-bit kernels, depending on
1001# hardware capabilities and scalability features of the kernel.
1002#
1003# ( If MAXSMP is enabled we just use the highest possible value and disable
1004#   interactive configuration. )
1005#
1006
1007config NR_CPUS_RANGE_BEGIN
1008	int
1009	default NR_CPUS_RANGE_END if MAXSMP
1010	default    1 if !SMP
1011	default    2
1012
1013config NR_CPUS_RANGE_END
1014	int
1015	depends on X86_32
1016	default   64 if  SMP &&  X86_BIGSMP
1017	default    8 if  SMP && !X86_BIGSMP
1018	default    1 if !SMP
1019
1020config NR_CPUS_RANGE_END
1021	int
1022	depends on X86_64
1023	default 8192 if  SMP && CPUMASK_OFFSTACK
1024	default  512 if  SMP && !CPUMASK_OFFSTACK
1025	default    1 if !SMP
1026
1027config NR_CPUS_DEFAULT
1028	int
1029	depends on X86_32
1030	default   32 if  X86_BIGSMP
1031	default    8 if  SMP
1032	default    1 if !SMP
1033
1034config NR_CPUS_DEFAULT
1035	int
1036	depends on X86_64
1037	default 8192 if  MAXSMP
1038	default   64 if  SMP
1039	default    1 if !SMP
1040
1041config NR_CPUS
1042	int "Maximum number of CPUs" if SMP && !MAXSMP
1043	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1044	default NR_CPUS_DEFAULT
1045	help
1046	  This allows you to specify the maximum number of CPUs which this
1047	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1048	  supported value is 8192, otherwise the maximum value is 512.  The
1049	  minimum value which makes sense is 2.
1050
1051	  This is purely to save memory: each supported CPU adds about 8KB
1052	  to the kernel image.
1053
1054config SCHED_CLUSTER
1055	bool "Cluster scheduler support"
1056	depends on SMP
1057	default y
1058	help
1059	  Cluster scheduler support improves the CPU scheduler's decision
1060	  making when dealing with machines that have clusters of CPUs.
1061	  Cluster usually means a couple of CPUs which are placed closely
1062	  by sharing mid-level caches, last-level cache tags or internal
1063	  busses.
1064
1065config SCHED_SMT
1066	def_bool y if SMP
1067
1068config SCHED_MC
1069	def_bool y
1070	prompt "Multi-core scheduler support"
1071	depends on SMP
1072	help
1073	  Multi-core scheduler support improves the CPU scheduler's decision
1074	  making when dealing with multi-core CPU chips at a cost of slightly
1075	  increased overhead in some places. If unsure say N here.
1076
1077config SCHED_MC_PRIO
1078	bool "CPU core priorities scheduler support"
1079	depends on SCHED_MC
1080	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1081	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1082	select CPU_FREQ
1083	default y
1084	help
1085	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1086	  core ordering determined at manufacturing time, which allows
1087	  certain cores to reach higher turbo frequencies (when running
1088	  single threaded workloads) than others.
1089
1090	  Enabling this kernel feature teaches the scheduler about
1091	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1092	  scheduler's CPU selection logic accordingly, so that higher
1093	  overall system performance can be achieved.
1094
1095	  This feature will have no effect on CPUs without this feature.
1096
1097	  If unsure say Y here.
1098
1099config UP_LATE_INIT
1100	def_bool y
1101	depends on !SMP && X86_LOCAL_APIC
1102
1103config X86_UP_APIC
1104	bool "Local APIC support on uniprocessors" if !PCI_MSI
1105	default PCI_MSI
1106	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1107	help
1108	  A local APIC (Advanced Programmable Interrupt Controller) is an
1109	  integrated interrupt controller in the CPU. If you have a single-CPU
1110	  system which has a processor with a local APIC, you can say Y here to
1111	  enable and use it. If you say Y here even though your machine doesn't
1112	  have a local APIC, then the kernel will still run with no slowdown at
1113	  all. The local APIC supports CPU-generated self-interrupts (timer,
1114	  performance counters), and the NMI watchdog which detects hard
1115	  lockups.
1116
1117config X86_UP_IOAPIC
1118	bool "IO-APIC support on uniprocessors"
1119	depends on X86_UP_APIC
1120	help
1121	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1122	  SMP-capable replacement for PC-style interrupt controllers. Most
1123	  SMP systems and many recent uniprocessor systems have one.
1124
1125	  If you have a single-CPU system with an IO-APIC, you can say Y here
1126	  to use it. If you say Y here even though your machine doesn't have
1127	  an IO-APIC, then the kernel will still run with no slowdown at all.
1128
1129config X86_LOCAL_APIC
1130	def_bool y
1131	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1132	select IRQ_DOMAIN_HIERARCHY
1133
1134config ACPI_MADT_WAKEUP
1135	def_bool y
1136	depends on X86_64
1137	depends on ACPI
1138	depends on SMP
1139	depends on X86_LOCAL_APIC
1140
1141config X86_IO_APIC
1142	def_bool y
1143	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1144
1145config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1146	bool "Reroute for broken boot IRQs"
1147	depends on X86_IO_APIC
1148	help
1149	  This option enables a workaround that fixes a source of
1150	  spurious interrupts. This is recommended when threaded
1151	  interrupt handling is used on systems where the generation of
1152	  superfluous "boot interrupts" cannot be disabled.
1153
1154	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1155	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1156	  kernel does during interrupt handling). On chipsets where this
1157	  boot IRQ generation cannot be disabled, this workaround keeps
1158	  the original IRQ line masked so that only the equivalent "boot
1159	  IRQ" is delivered to the CPUs. The workaround also tells the
1160	  kernel to set up the IRQ handler on the boot IRQ line. In this
1161	  way only one interrupt is delivered to the kernel. Otherwise
1162	  the spurious second interrupt may cause the kernel to bring
1163	  down (vital) interrupt lines.
1164
1165	  Only affects "broken" chipsets. Interrupt sharing may be
1166	  increased on these systems.
1167
1168config X86_MCE
1169	bool "Machine Check / overheating reporting"
1170	select GENERIC_ALLOCATOR
1171	default y
1172	help
1173	  Machine Check support allows the processor to notify the
1174	  kernel if it detects a problem (e.g. overheating, data corruption).
1175	  The action the kernel takes depends on the severity of the problem,
1176	  ranging from warning messages to halting the machine.
1177
1178config X86_MCELOG_LEGACY
1179	bool "Support for deprecated /dev/mcelog character device"
1180	depends on X86_MCE
1181	help
1182	  Enable support for /dev/mcelog which is needed by the old mcelog
1183	  userspace logging daemon. Consider switching to the new generation
1184	  rasdaemon solution.
1185
1186config X86_MCE_INTEL
1187	def_bool y
1188	prompt "Intel MCE features"
1189	depends on X86_MCE && X86_LOCAL_APIC
1190	help
1191	  Additional support for intel specific MCE features such as
1192	  the thermal monitor.
1193
1194config X86_MCE_AMD
1195	def_bool y
1196	prompt "AMD MCE features"
1197	depends on X86_MCE && X86_LOCAL_APIC
1198	help
1199	  Additional support for AMD specific MCE features such as
1200	  the DRAM Error Threshold.
1201
1202config X86_ANCIENT_MCE
1203	bool "Support for old Pentium 5 / WinChip machine checks"
1204	depends on X86_32 && X86_MCE
1205	help
1206	  Include support for machine check handling on old Pentium 5 or WinChip
1207	  systems. These typically need to be enabled explicitly on the command
1208	  line.
1209
1210config X86_MCE_THRESHOLD
1211	depends on X86_MCE_AMD || X86_MCE_INTEL
1212	def_bool y
1213
1214config X86_MCE_INJECT
1215	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1216	tristate "Machine check injector support"
1217	help
1218	  Provide support for injecting machine checks for testing purposes.
1219	  If you don't know what a machine check is and you don't do kernel
1220	  QA it is safe to say n.
1221
1222source "arch/x86/events/Kconfig"
1223
1224config X86_LEGACY_VM86
1225	bool "Legacy VM86 support"
1226	depends on X86_32
1227	help
1228	  This option allows user programs to put the CPU into V8086
1229	  mode, which is an 80286-era approximation of 16-bit real mode.
1230
1231	  Some very old versions of X and/or vbetool require this option
1232	  for user mode setting.  Similarly, DOSEMU will use it if
1233	  available to accelerate real mode DOS programs.  However, any
1234	  recent version of DOSEMU, X, or vbetool should be fully
1235	  functional even without kernel VM86 support, as they will all
1236	  fall back to software emulation. Nevertheless, if you are using
1237	  a 16-bit DOS program where 16-bit performance matters, vm86
1238	  mode might be faster than emulation and you might want to
1239	  enable this option.
1240
1241	  Note that any app that works on a 64-bit kernel is unlikely to
1242	  need this option, as 64-bit kernels don't, and can't, support
1243	  V8086 mode. This option is also unrelated to 16-bit protected
1244	  mode and is not needed to run most 16-bit programs under Wine.
1245
1246	  Enabling this option increases the complexity of the kernel
1247	  and slows down exception handling a tiny bit.
1248
1249	  If unsure, say N here.
1250
1251config VM86
1252	bool
1253	default X86_LEGACY_VM86
1254
1255config X86_16BIT
1256	bool "Enable support for 16-bit segments" if EXPERT
1257	default y
1258	depends on MODIFY_LDT_SYSCALL
1259	help
1260	  This option is required by programs like Wine to run 16-bit
1261	  protected mode legacy code on x86 processors.  Disabling
1262	  this option saves about 300 bytes on i386, or around 6K text
1263	  plus 16K runtime memory on x86-64,
1264
1265config X86_ESPFIX32
1266	def_bool y
1267	depends on X86_16BIT && X86_32
1268
1269config X86_ESPFIX64
1270	def_bool y
1271	depends on X86_16BIT && X86_64
1272
1273config X86_VSYSCALL_EMULATION
1274	bool "Enable vsyscall emulation" if EXPERT
1275	default y
1276	depends on X86_64
1277	help
1278	  This enables emulation of the legacy vsyscall page.  Disabling
1279	  it is roughly equivalent to booting with vsyscall=none, except
1280	  that it will also disable the helpful warning if a program
1281	  tries to use a vsyscall.  With this option set to N, offending
1282	  programs will just segfault, citing addresses of the form
1283	  0xffffffffff600?00.
1284
1285	  This option is required by many programs built before 2013, and
1286	  care should be used even with newer programs if set to N.
1287
1288	  Disabling this option saves about 7K of kernel size and
1289	  possibly 4K of additional runtime pagetable memory.
1290
1291config X86_IOPL_IOPERM
1292	bool "IOPERM and IOPL Emulation"
1293	default y
1294	help
1295	  This enables the ioperm() and iopl() syscalls which are necessary
1296	  for legacy applications.
1297
1298	  Legacy IOPL support is an overbroad mechanism which allows user
1299	  space aside of accessing all 65536 I/O ports also to disable
1300	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1301	  capabilities and permission from potentially active security
1302	  modules.
1303
1304	  The emulation restricts the functionality of the syscall to
1305	  only allowing the full range I/O port access, but prevents the
1306	  ability to disable interrupts from user space which would be
1307	  granted if the hardware IOPL mechanism would be used.
1308
1309config TOSHIBA
1310	tristate "Toshiba Laptop support"
1311	depends on X86_32
1312	help
1313	  This adds a driver to safely access the System Management Mode of
1314	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1315	  not work on models with a Phoenix BIOS. The System Management Mode
1316	  is used to set the BIOS and power saving options on Toshiba portables.
1317
1318	  For information on utilities to make use of this driver see the
1319	  Toshiba Linux utilities web site at:
1320	  <http://www.buzzard.org.uk/toshiba/>.
1321
1322	  Say Y if you intend to run this kernel on a Toshiba portable.
1323	  Say N otherwise.
1324
1325config X86_REBOOTFIXUPS
1326	bool "Enable X86 board specific fixups for reboot"
1327	depends on X86_32
1328	help
1329	  This enables chipset and/or board specific fixups to be done
1330	  in order to get reboot to work correctly. This is only needed on
1331	  some combinations of hardware and BIOS. The symptom, for which
1332	  this config is intended, is when reboot ends with a stalled/hung
1333	  system.
1334
1335	  Currently, the only fixup is for the Geode machines using
1336	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1337
1338	  Say Y if you want to enable the fixup. Currently, it's safe to
1339	  enable this option even if you don't need it.
1340	  Say N otherwise.
1341
1342config MICROCODE
1343	def_bool y
1344	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1345	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1346
1347config MICROCODE_INITRD32
1348	def_bool y
1349	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1350
1351config MICROCODE_LATE_LOADING
1352	bool "Late microcode loading (DANGEROUS)"
1353	default n
1354	depends on MICROCODE && SMP
1355	help
1356	  Loading microcode late, when the system is up and executing instructions
1357	  is a tricky business and should be avoided if possible. Just the sequence
1358	  of synchronizing all cores and SMT threads is one fragile dance which does
1359	  not guarantee that cores might not softlock after the loading. Therefore,
1360	  use this at your own risk. Late loading taints the kernel unless the
1361	  microcode header indicates that it is safe for late loading via the
1362	  minimal revision check. This minimal revision check can be enforced on
1363	  the kernel command line with "microcode.minrev=Y".
1364
1365config MICROCODE_LATE_FORCE_MINREV
1366	bool "Enforce late microcode loading minimal revision check"
1367	default n
1368	depends on MICROCODE_LATE_LOADING
1369	help
1370	  To prevent that users load microcode late which modifies already
1371	  in use features, newer microcode patches have a minimum revision field
1372	  in the microcode header, which tells the kernel which minimum
1373	  revision must be active in the CPU to safely load that new microcode
1374	  late into the running system. If disabled the check will not
1375	  be enforced but the kernel will be tainted when the minimal
1376	  revision check fails.
1377
1378	  This minimal revision check can also be controlled via the
1379	  "microcode.minrev" parameter on the kernel command line.
1380
1381	  If unsure say Y.
1382
1383config X86_MSR
1384	tristate "/dev/cpu/*/msr - Model-specific register support"
1385	help
1386	  This device gives privileged processes access to the x86
1387	  Model-Specific Registers (MSRs).  It is a character device with
1388	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1389	  MSR accesses are directed to a specific CPU on multi-processor
1390	  systems.
1391
1392config X86_CPUID
1393	tristate "/dev/cpu/*/cpuid - CPU information support"
1394	help
1395	  This device gives processes access to the x86 CPUID instruction to
1396	  be executed on a specific processor.  It is a character device
1397	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1398	  /dev/cpu/31/cpuid.
1399
1400choice
1401	prompt "High Memory Support"
1402	default HIGHMEM4G
1403	depends on X86_32
1404
1405config NOHIGHMEM
1406	bool "off"
1407	help
1408	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1409	  However, the address space of 32-bit x86 processors is only 4
1410	  Gigabytes large. That means that, if you have a large amount of
1411	  physical memory, not all of it can be "permanently mapped" by the
1412	  kernel. The physical memory that's not permanently mapped is called
1413	  "high memory".
1414
1415	  If you are compiling a kernel which will never run on a machine with
1416	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1417	  choice and suitable for most users). This will result in a "3GB/1GB"
1418	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1419	  space and the remaining part of the 4GB virtual memory space is used
1420	  by the kernel to permanently map as much physical memory as
1421	  possible.
1422
1423	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1424	  answer "4GB" here.
1425
1426	  If more than 4 Gigabytes is used then answer "64GB" here. This
1427	  selection turns Intel PAE (Physical Address Extension) mode on.
1428	  PAE implements 3-level paging on IA32 processors. PAE is fully
1429	  supported by Linux, PAE mode is implemented on all recent Intel
1430	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1431	  then the kernel will not boot on CPUs that don't support PAE!
1432
1433	  The actual amount of total physical memory will either be
1434	  auto detected or can be forced by using a kernel command line option
1435	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1436	  your boot loader (lilo or loadlin) about how to pass options to the
1437	  kernel at boot time.)
1438
1439	  If unsure, say "off".
1440
1441config HIGHMEM4G
1442	bool "4GB"
1443	help
1444	  Select this if you have a 32-bit processor and between 1 and 4
1445	  gigabytes of physical RAM.
1446
1447config HIGHMEM64G
1448	bool "64GB"
1449	depends on X86_HAVE_PAE
1450	select X86_PAE
1451	help
1452	  Select this if you have a 32-bit processor and more than 4
1453	  gigabytes of physical RAM.
1454
1455endchoice
1456
1457choice
1458	prompt "Memory split" if EXPERT
1459	default VMSPLIT_3G
1460	depends on X86_32
1461	help
1462	  Select the desired split between kernel and user memory.
1463
1464	  If the address range available to the kernel is less than the
1465	  physical memory installed, the remaining memory will be available
1466	  as "high memory". Accessing high memory is a little more costly
1467	  than low memory, as it needs to be mapped into the kernel first.
1468	  Note that increasing the kernel address space limits the range
1469	  available to user programs, making the address space there
1470	  tighter.  Selecting anything other than the default 3G/1G split
1471	  will also likely make your kernel incompatible with binary-only
1472	  kernel modules.
1473
1474	  If you are not absolutely sure what you are doing, leave this
1475	  option alone!
1476
1477	config VMSPLIT_3G
1478		bool "3G/1G user/kernel split"
1479	config VMSPLIT_3G_OPT
1480		depends on !X86_PAE
1481		bool "3G/1G user/kernel split (for full 1G low memory)"
1482	config VMSPLIT_2G
1483		bool "2G/2G user/kernel split"
1484	config VMSPLIT_2G_OPT
1485		depends on !X86_PAE
1486		bool "2G/2G user/kernel split (for full 2G low memory)"
1487	config VMSPLIT_1G
1488		bool "1G/3G user/kernel split"
1489endchoice
1490
1491config PAGE_OFFSET
1492	hex
1493	default 0xB0000000 if VMSPLIT_3G_OPT
1494	default 0x80000000 if VMSPLIT_2G
1495	default 0x78000000 if VMSPLIT_2G_OPT
1496	default 0x40000000 if VMSPLIT_1G
1497	default 0xC0000000
1498	depends on X86_32
1499
1500config HIGHMEM
1501	def_bool y
1502	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1503
1504config X86_PAE
1505	bool "PAE (Physical Address Extension) Support"
1506	depends on X86_32 && X86_HAVE_PAE
1507	select PHYS_ADDR_T_64BIT
1508	select SWIOTLB
1509	help
1510	  PAE is required for NX support, and furthermore enables
1511	  larger swapspace support for non-overcommit purposes. It
1512	  has the cost of more pagetable lookup overhead, and also
1513	  consumes more pagetable space per process.
1514
1515config X86_5LEVEL
1516	bool "Enable 5-level page tables support"
1517	default y
1518	select DYNAMIC_MEMORY_LAYOUT
1519	select SPARSEMEM_VMEMMAP
1520	depends on X86_64
1521	help
1522	  5-level paging enables access to larger address space:
1523	  up to 128 PiB of virtual address space and 4 PiB of
1524	  physical address space.
1525
1526	  It will be supported by future Intel CPUs.
1527
1528	  A kernel with the option enabled can be booted on machines that
1529	  support 4- or 5-level paging.
1530
1531	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1532	  information.
1533
1534	  Say N if unsure.
1535
1536config X86_DIRECT_GBPAGES
1537	def_bool y
1538	depends on X86_64
1539	help
1540	  Certain kernel features effectively disable kernel
1541	  linear 1 GB mappings (even if the CPU otherwise
1542	  supports them), so don't confuse the user by printing
1543	  that we have them enabled.
1544
1545config X86_CPA_STATISTICS
1546	bool "Enable statistic for Change Page Attribute"
1547	depends on DEBUG_FS
1548	help
1549	  Expose statistics about the Change Page Attribute mechanism, which
1550	  helps to determine the effectiveness of preserving large and huge
1551	  page mappings when mapping protections are changed.
1552
1553config X86_MEM_ENCRYPT
1554	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1555	select DYNAMIC_PHYSICAL_MASK
1556	def_bool n
1557
1558config AMD_MEM_ENCRYPT
1559	bool "AMD Secure Memory Encryption (SME) support"
1560	depends on X86_64 && CPU_SUP_AMD
1561	depends on EFI_STUB
1562	select DMA_COHERENT_POOL
1563	select ARCH_USE_MEMREMAP_PROT
1564	select INSTRUCTION_DECODER
1565	select ARCH_HAS_CC_PLATFORM
1566	select X86_MEM_ENCRYPT
1567	select UNACCEPTED_MEMORY
1568	select CRYPTO_LIB_AESGCM
1569	help
1570	  Say yes to enable support for the encryption of system memory.
1571	  This requires an AMD processor that supports Secure Memory
1572	  Encryption (SME).
1573
1574# Common NUMA Features
1575config NUMA
1576	bool "NUMA Memory Allocation and Scheduler Support"
1577	depends on SMP
1578	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1579	default y if X86_BIGSMP
1580	select USE_PERCPU_NUMA_NODE_ID
1581	select OF_NUMA if OF
1582	help
1583	  Enable NUMA (Non-Uniform Memory Access) support.
1584
1585	  The kernel will try to allocate memory used by a CPU on the
1586	  local memory controller of the CPU and add some more
1587	  NUMA awareness to the kernel.
1588
1589	  For 64-bit this is recommended if the system is Intel Core i7
1590	  (or later), AMD Opteron, or EM64T NUMA.
1591
1592	  For 32-bit this is only needed if you boot a 32-bit
1593	  kernel on a 64-bit NUMA platform.
1594
1595	  Otherwise, you should say N.
1596
1597config AMD_NUMA
1598	def_bool y
1599	prompt "Old style AMD Opteron NUMA detection"
1600	depends on X86_64 && NUMA && PCI
1601	help
1602	  Enable AMD NUMA node topology detection.  You should say Y here if
1603	  you have a multi processor AMD system. This uses an old method to
1604	  read the NUMA configuration directly from the builtin Northbridge
1605	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1606	  which also takes priority if both are compiled in.
1607
1608config X86_64_ACPI_NUMA
1609	def_bool y
1610	prompt "ACPI NUMA detection"
1611	depends on X86_64 && NUMA && ACPI && PCI
1612	select ACPI_NUMA
1613	help
1614	  Enable ACPI SRAT based node topology detection.
1615
1616config NODES_SHIFT
1617	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1618	range 1 10
1619	default "10" if MAXSMP
1620	default "6" if X86_64
1621	default "3"
1622	depends on NUMA
1623	help
1624	  Specify the maximum number of NUMA Nodes available on the target
1625	  system.  Increases memory reserved to accommodate various tables.
1626
1627config ARCH_FLATMEM_ENABLE
1628	def_bool y
1629	depends on X86_32 && !NUMA
1630
1631config ARCH_SPARSEMEM_ENABLE
1632	def_bool y
1633	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1634	select SPARSEMEM_STATIC if X86_32
1635	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1636
1637config ARCH_SPARSEMEM_DEFAULT
1638	def_bool X86_64 || (NUMA && X86_32)
1639
1640config ARCH_SELECT_MEMORY_MODEL
1641	def_bool y
1642	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1643
1644config ARCH_MEMORY_PROBE
1645	bool "Enable sysfs memory/probe interface"
1646	depends on MEMORY_HOTPLUG
1647	help
1648	  This option enables a sysfs memory/probe interface for testing.
1649	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1650	  If you are unsure how to answer this question, answer N.
1651
1652config ARCH_PROC_KCORE_TEXT
1653	def_bool y
1654	depends on X86_64 && PROC_KCORE
1655
1656config ILLEGAL_POINTER_VALUE
1657	hex
1658	default 0 if X86_32
1659	default 0xdead000000000000 if X86_64
1660
1661config X86_PMEM_LEGACY_DEVICE
1662	bool
1663
1664config X86_PMEM_LEGACY
1665	tristate "Support non-standard NVDIMMs and ADR protected memory"
1666	depends on PHYS_ADDR_T_64BIT
1667	depends on BLK_DEV
1668	select X86_PMEM_LEGACY_DEVICE
1669	select NUMA_KEEP_MEMINFO if NUMA
1670	select LIBNVDIMM
1671	help
1672	  Treat memory marked using the non-standard e820 type of 12 as used
1673	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1674	  The kernel will offer these regions to the 'pmem' driver so
1675	  they can be used for persistent storage.
1676
1677	  Say Y if unsure.
1678
1679config HIGHPTE
1680	bool "Allocate 3rd-level pagetables from highmem"
1681	depends on HIGHMEM
1682	help
1683	  The VM uses one page table entry for each page of physical memory.
1684	  For systems with a lot of RAM, this can be wasteful of precious
1685	  low memory.  Setting this option will put user-space page table
1686	  entries in high memory.
1687
1688config X86_CHECK_BIOS_CORRUPTION
1689	bool "Check for low memory corruption"
1690	help
1691	  Periodically check for memory corruption in low memory, which
1692	  is suspected to be caused by BIOS.  Even when enabled in the
1693	  configuration, it is disabled at runtime.  Enable it by
1694	  setting "memory_corruption_check=1" on the kernel command
1695	  line.  By default it scans the low 64k of memory every 60
1696	  seconds; see the memory_corruption_check_size and
1697	  memory_corruption_check_period parameters in
1698	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1699
1700	  When enabled with the default parameters, this option has
1701	  almost no overhead, as it reserves a relatively small amount
1702	  of memory and scans it infrequently.  It both detects corruption
1703	  and prevents it from affecting the running system.
1704
1705	  It is, however, intended as a diagnostic tool; if repeatable
1706	  BIOS-originated corruption always affects the same memory,
1707	  you can use memmap= to prevent the kernel from using that
1708	  memory.
1709
1710config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1711	bool "Set the default setting of memory_corruption_check"
1712	depends on X86_CHECK_BIOS_CORRUPTION
1713	default y
1714	help
1715	  Set whether the default state of memory_corruption_check is
1716	  on or off.
1717
1718config MATH_EMULATION
1719	bool
1720	depends on MODIFY_LDT_SYSCALL
1721	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1722	help
1723	  Linux can emulate a math coprocessor (used for floating point
1724	  operations) if you don't have one. 486DX and Pentium processors have
1725	  a math coprocessor built in, 486SX and 386 do not, unless you added
1726	  a 487DX or 387, respectively. (The messages during boot time can
1727	  give you some hints here ["man dmesg"].) Everyone needs either a
1728	  coprocessor or this emulation.
1729
1730	  If you don't have a math coprocessor, you need to say Y here; if you
1731	  say Y here even though you have a coprocessor, the coprocessor will
1732	  be used nevertheless. (This behavior can be changed with the kernel
1733	  command line option "no387", which comes handy if your coprocessor
1734	  is broken. Try "man bootparam" or see the documentation of your boot
1735	  loader (lilo or loadlin) about how to pass options to the kernel at
1736	  boot time.) This means that it is a good idea to say Y here if you
1737	  intend to use this kernel on different machines.
1738
1739	  More information about the internals of the Linux math coprocessor
1740	  emulation can be found in <file:arch/x86/math-emu/README>.
1741
1742	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1743	  kernel, it won't hurt.
1744
1745config MTRR
1746	def_bool y
1747	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1748	help
1749	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1750	  the Memory Type Range Registers (MTRRs) may be used to control
1751	  processor access to memory ranges. This is most useful if you have
1752	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1753	  allows bus write transfers to be combined into a larger transfer
1754	  before bursting over the PCI/AGP bus. This can increase performance
1755	  of image write operations 2.5 times or more. Saying Y here creates a
1756	  /proc/mtrr file which may be used to manipulate your processor's
1757	  MTRRs. Typically the X server should use this.
1758
1759	  This code has a reasonably generic interface so that similar
1760	  control registers on other processors can be easily supported
1761	  as well:
1762
1763	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1764	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1765	  these, the ARRs are used to emulate the MTRRs.
1766	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1767	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1768	  write-combining. All of these processors are supported by this code
1769	  and it makes sense to say Y here if you have one of them.
1770
1771	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1772	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1773	  can lead to all sorts of problems, so it's good to say Y here.
1774
1775	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1776	  just add about 9 KB to your kernel.
1777
1778	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1779
1780config MTRR_SANITIZER
1781	def_bool y
1782	prompt "MTRR cleanup support"
1783	depends on MTRR
1784	help
1785	  Convert MTRR layout from continuous to discrete, so X drivers can
1786	  add writeback entries.
1787
1788	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1789	  The largest mtrr entry size for a continuous block can be set with
1790	  mtrr_chunk_size.
1791
1792	  If unsure, say Y.
1793
1794config MTRR_SANITIZER_ENABLE_DEFAULT
1795	int "MTRR cleanup enable value (0-1)"
1796	range 0 1
1797	default "0"
1798	depends on MTRR_SANITIZER
1799	help
1800	  Enable mtrr cleanup default value
1801
1802config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1803	int "MTRR cleanup spare reg num (0-7)"
1804	range 0 7
1805	default "1"
1806	depends on MTRR_SANITIZER
1807	help
1808	  mtrr cleanup spare entries default, it can be changed via
1809	  mtrr_spare_reg_nr=N on the kernel command line.
1810
1811config X86_PAT
1812	def_bool y
1813	prompt "x86 PAT support" if EXPERT
1814	depends on MTRR
1815	select ARCH_USES_PG_ARCH_2
1816	help
1817	  Use PAT attributes to setup page level cache control.
1818
1819	  PATs are the modern equivalents of MTRRs and are much more
1820	  flexible than MTRRs.
1821
1822	  Say N here if you see bootup problems (boot crash, boot hang,
1823	  spontaneous reboots) or a non-working video driver.
1824
1825	  If unsure, say Y.
1826
1827config X86_UMIP
1828	def_bool y
1829	prompt "User Mode Instruction Prevention" if EXPERT
1830	help
1831	  User Mode Instruction Prevention (UMIP) is a security feature in
1832	  some x86 processors. If enabled, a general protection fault is
1833	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1834	  executed in user mode. These instructions unnecessarily expose
1835	  information about the hardware state.
1836
1837	  The vast majority of applications do not use these instructions.
1838	  For the very few that do, software emulation is provided in
1839	  specific cases in protected and virtual-8086 modes. Emulated
1840	  results are dummy.
1841
1842config CC_HAS_IBT
1843	# GCC >= 9 and binutils >= 2.29
1844	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1845	# Clang/LLVM >= 14
1846	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1847	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1848	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1849		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1850		  $(as-instr,endbr64)
1851
1852config X86_CET
1853	def_bool n
1854	help
1855	  CET features configured (Shadow stack or IBT)
1856
1857config X86_KERNEL_IBT
1858	prompt "Indirect Branch Tracking"
1859	def_bool y
1860	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1861	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1862	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1863	select OBJTOOL
1864	select X86_CET
1865	help
1866	  Build the kernel with support for Indirect Branch Tracking, a
1867	  hardware support course-grain forward-edge Control Flow Integrity
1868	  protection. It enforces that all indirect calls must land on
1869	  an ENDBR instruction, as such, the compiler will instrument the
1870	  code with them to make this happen.
1871
1872	  In addition to building the kernel with IBT, seal all functions that
1873	  are not indirect call targets, avoiding them ever becoming one.
1874
1875	  This requires LTO like objtool runs and will slow down the build. It
1876	  does significantly reduce the number of ENDBR instructions in the
1877	  kernel image.
1878
1879config X86_INTEL_MEMORY_PROTECTION_KEYS
1880	prompt "Memory Protection Keys"
1881	def_bool y
1882	# Note: only available in 64-bit mode
1883	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1884	select ARCH_USES_HIGH_VMA_FLAGS
1885	select ARCH_HAS_PKEYS
1886	help
1887	  Memory Protection Keys provides a mechanism for enforcing
1888	  page-based protections, but without requiring modification of the
1889	  page tables when an application changes protection domains.
1890
1891	  For details, see Documentation/core-api/protection-keys.rst
1892
1893	  If unsure, say y.
1894
1895config ARCH_PKEY_BITS
1896	int
1897	default 4
1898
1899choice
1900	prompt "TSX enable mode"
1901	depends on CPU_SUP_INTEL
1902	default X86_INTEL_TSX_MODE_OFF
1903	help
1904	  Intel's TSX (Transactional Synchronization Extensions) feature
1905	  allows to optimize locking protocols through lock elision which
1906	  can lead to a noticeable performance boost.
1907
1908	  On the other hand it has been shown that TSX can be exploited
1909	  to form side channel attacks (e.g. TAA) and chances are there
1910	  will be more of those attacks discovered in the future.
1911
1912	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1913	  might override this decision by tsx=on the command line parameter.
1914	  Even with TSX enabled, the kernel will attempt to enable the best
1915	  possible TAA mitigation setting depending on the microcode available
1916	  for the particular machine.
1917
1918	  This option allows to set the default tsx mode between tsx=on, =off
1919	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1920	  details.
1921
1922	  Say off if not sure, auto if TSX is in use but it should be used on safe
1923	  platforms or on if TSX is in use and the security aspect of tsx is not
1924	  relevant.
1925
1926config X86_INTEL_TSX_MODE_OFF
1927	bool "off"
1928	help
1929	  TSX is disabled if possible - equals to tsx=off command line parameter.
1930
1931config X86_INTEL_TSX_MODE_ON
1932	bool "on"
1933	help
1934	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1935	  line parameter.
1936
1937config X86_INTEL_TSX_MODE_AUTO
1938	bool "auto"
1939	help
1940	  TSX is enabled on TSX capable HW that is believed to be safe against
1941	  side channel attacks- equals the tsx=auto command line parameter.
1942endchoice
1943
1944config X86_SGX
1945	bool "Software Guard eXtensions (SGX)"
1946	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1947	depends on CRYPTO=y
1948	depends on CRYPTO_SHA256=y
1949	select MMU_NOTIFIER
1950	select NUMA_KEEP_MEMINFO if NUMA
1951	select XARRAY_MULTI
1952	help
1953	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1954	  that can be used by applications to set aside private regions of code
1955	  and data, referred to as enclaves. An enclave's private memory can
1956	  only be accessed by code running within the enclave. Accesses from
1957	  outside the enclave, including other enclaves, are disallowed by
1958	  hardware.
1959
1960	  If unsure, say N.
1961
1962config X86_USER_SHADOW_STACK
1963	bool "X86 userspace shadow stack"
1964	depends on AS_WRUSS
1965	depends on X86_64
1966	select ARCH_USES_HIGH_VMA_FLAGS
1967	select ARCH_HAS_USER_SHADOW_STACK
1968	select X86_CET
1969	help
1970	  Shadow stack protection is a hardware feature that detects function
1971	  return address corruption.  This helps mitigate ROP attacks.
1972	  Applications must be enabled to use it, and old userspace does not
1973	  get protection "for free".
1974
1975	  CPUs supporting shadow stacks were first released in 2020.
1976
1977	  See Documentation/arch/x86/shstk.rst for more information.
1978
1979	  If unsure, say N.
1980
1981config INTEL_TDX_HOST
1982	bool "Intel Trust Domain Extensions (TDX) host support"
1983	depends on CPU_SUP_INTEL
1984	depends on X86_64
1985	depends on KVM_INTEL
1986	depends on X86_X2APIC
1987	select ARCH_KEEP_MEMBLOCK
1988	depends on CONTIG_ALLOC
1989	depends on !KEXEC_CORE
1990	depends on X86_MCE
1991	help
1992	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1993	  host and certain physical attacks.  This option enables necessary TDX
1994	  support in the host kernel to run confidential VMs.
1995
1996	  If unsure, say N.
1997
1998config EFI
1999	bool "EFI runtime service support"
2000	depends on ACPI
2001	select UCS2_STRING
2002	select EFI_RUNTIME_WRAPPERS
2003	select ARCH_USE_MEMREMAP_PROT
2004	select EFI_RUNTIME_MAP if KEXEC_CORE
2005	help
2006	  This enables the kernel to use EFI runtime services that are
2007	  available (such as the EFI variable services).
2008
2009	  This option is only useful on systems that have EFI firmware.
2010	  In addition, you should use the latest ELILO loader available
2011	  at <http://elilo.sourceforge.net> in order to take advantage
2012	  of EFI runtime services. However, even with this option, the
2013	  resultant kernel should continue to boot on existing non-EFI
2014	  platforms.
2015
2016config EFI_STUB
2017	bool "EFI stub support"
2018	depends on EFI
2019	select RELOCATABLE
2020	help
2021	  This kernel feature allows a bzImage to be loaded directly
2022	  by EFI firmware without the use of a bootloader.
2023
2024	  See Documentation/admin-guide/efi-stub.rst for more information.
2025
2026config EFI_HANDOVER_PROTOCOL
2027	bool "EFI handover protocol (DEPRECATED)"
2028	depends on EFI_STUB
2029	default y
2030	help
2031	  Select this in order to include support for the deprecated EFI
2032	  handover protocol, which defines alternative entry points into the
2033	  EFI stub.  This is a practice that has no basis in the UEFI
2034	  specification, and requires a priori knowledge on the part of the
2035	  bootloader about Linux/x86 specific ways of passing the command line
2036	  and initrd, and where in memory those assets may be loaded.
2037
2038	  If in doubt, say Y. Even though the corresponding support is not
2039	  present in upstream GRUB or other bootloaders, most distros build
2040	  GRUB with numerous downstream patches applied, and may rely on the
2041	  handover protocol as as result.
2042
2043config EFI_MIXED
2044	bool "EFI mixed-mode support"
2045	depends on EFI_STUB && X86_64
2046	help
2047	  Enabling this feature allows a 64-bit kernel to be booted
2048	  on a 32-bit firmware, provided that your CPU supports 64-bit
2049	  mode.
2050
2051	  Note that it is not possible to boot a mixed-mode enabled
2052	  kernel via the EFI boot stub - a bootloader that supports
2053	  the EFI handover protocol must be used.
2054
2055	  If unsure, say N.
2056
2057config EFI_RUNTIME_MAP
2058	bool "Export EFI runtime maps to sysfs" if EXPERT
2059	depends on EFI
2060	help
2061	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2062	  That memory map is required by the 2nd kernel to set up EFI virtual
2063	  mappings after kexec, but can also be used for debugging purposes.
2064
2065	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2066
2067source "kernel/Kconfig.hz"
2068
2069config ARCH_SUPPORTS_KEXEC
2070	def_bool y
2071
2072config ARCH_SUPPORTS_KEXEC_FILE
2073	def_bool X86_64
2074
2075config ARCH_SELECTS_KEXEC_FILE
2076	def_bool y
2077	depends on KEXEC_FILE
2078	select HAVE_IMA_KEXEC if IMA
2079
2080config ARCH_SUPPORTS_KEXEC_PURGATORY
2081	def_bool y
2082
2083config ARCH_SUPPORTS_KEXEC_SIG
2084	def_bool y
2085
2086config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2087	def_bool y
2088
2089config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2090	def_bool y
2091
2092config ARCH_SUPPORTS_KEXEC_JUMP
2093	def_bool y
2094
2095config ARCH_SUPPORTS_CRASH_DUMP
2096	def_bool X86_64 || (X86_32 && HIGHMEM)
2097
2098config ARCH_DEFAULT_CRASH_DUMP
2099	def_bool y
2100
2101config ARCH_SUPPORTS_CRASH_HOTPLUG
2102	def_bool y
2103
2104config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2105	def_bool CRASH_RESERVE
2106
2107config PHYSICAL_START
2108	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2109	default "0x1000000"
2110	help
2111	  This gives the physical address where the kernel is loaded.
2112
2113	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2114	  will decompress itself to above physical address and run from there.
2115	  Otherwise, bzImage will run from the address where it has been loaded
2116	  by the boot loader. The only exception is if it is loaded below the
2117	  above physical address, in which case it will relocate itself there.
2118
2119	  In normal kdump cases one does not have to set/change this option
2120	  as now bzImage can be compiled as a completely relocatable image
2121	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2122	  address. This option is mainly useful for the folks who don't want
2123	  to use a bzImage for capturing the crash dump and want to use a
2124	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2125	  to be specifically compiled to run from a specific memory area
2126	  (normally a reserved region) and this option comes handy.
2127
2128	  So if you are using bzImage for capturing the crash dump,
2129	  leave the value here unchanged to 0x1000000 and set
2130	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2131	  for capturing the crash dump change this value to start of
2132	  the reserved region.  In other words, it can be set based on
2133	  the "X" value as specified in the "crashkernel=YM@XM"
2134	  command line boot parameter passed to the panic-ed
2135	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2136	  for more details about crash dumps.
2137
2138	  Usage of bzImage for capturing the crash dump is recommended as
2139	  one does not have to build two kernels. Same kernel can be used
2140	  as production kernel and capture kernel. Above option should have
2141	  gone away after relocatable bzImage support is introduced. But it
2142	  is present because there are users out there who continue to use
2143	  vmlinux for dump capture. This option should go away down the
2144	  line.
2145
2146	  Don't change this unless you know what you are doing.
2147
2148config RELOCATABLE
2149	bool "Build a relocatable kernel"
2150	default y
2151	help
2152	  This builds a kernel image that retains relocation information
2153	  so it can be loaded someplace besides the default 1MB.
2154	  The relocations tend to make the kernel binary about 10% larger,
2155	  but are discarded at runtime.
2156
2157	  One use is for the kexec on panic case where the recovery kernel
2158	  must live at a different physical address than the primary
2159	  kernel.
2160
2161	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2162	  it has been loaded at and the compile time physical address
2163	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2164
2165config RANDOMIZE_BASE
2166	bool "Randomize the address of the kernel image (KASLR)"
2167	depends on RELOCATABLE
2168	default y
2169	help
2170	  In support of Kernel Address Space Layout Randomization (KASLR),
2171	  this randomizes the physical address at which the kernel image
2172	  is decompressed and the virtual address where the kernel
2173	  image is mapped, as a security feature that deters exploit
2174	  attempts relying on knowledge of the location of kernel
2175	  code internals.
2176
2177	  On 64-bit, the kernel physical and virtual addresses are
2178	  randomized separately. The physical address will be anywhere
2179	  between 16MB and the top of physical memory (up to 64TB). The
2180	  virtual address will be randomized from 16MB up to 1GB (9 bits
2181	  of entropy). Note that this also reduces the memory space
2182	  available to kernel modules from 1.5GB to 1GB.
2183
2184	  On 32-bit, the kernel physical and virtual addresses are
2185	  randomized together. They will be randomized from 16MB up to
2186	  512MB (8 bits of entropy).
2187
2188	  Entropy is generated using the RDRAND instruction if it is
2189	  supported. If RDTSC is supported, its value is mixed into
2190	  the entropy pool as well. If neither RDRAND nor RDTSC are
2191	  supported, then entropy is read from the i8254 timer. The
2192	  usable entropy is limited by the kernel being built using
2193	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2194	  minimum of 2MB. As a result, only 10 bits of entropy are
2195	  theoretically possible, but the implementations are further
2196	  limited due to memory layouts.
2197
2198	  If unsure, say Y.
2199
2200# Relocation on x86 needs some additional build support
2201config X86_NEED_RELOCS
2202	def_bool y
2203	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2204
2205config PHYSICAL_ALIGN
2206	hex "Alignment value to which kernel should be aligned"
2207	default "0x200000"
2208	range 0x2000 0x1000000 if X86_32
2209	range 0x200000 0x1000000 if X86_64
2210	help
2211	  This value puts the alignment restrictions on physical address
2212	  where kernel is loaded and run from. Kernel is compiled for an
2213	  address which meets above alignment restriction.
2214
2215	  If bootloader loads the kernel at a non-aligned address and
2216	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2217	  address aligned to above value and run from there.
2218
2219	  If bootloader loads the kernel at a non-aligned address and
2220	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2221	  load address and decompress itself to the address it has been
2222	  compiled for and run from there. The address for which kernel is
2223	  compiled already meets above alignment restrictions. Hence the
2224	  end result is that kernel runs from a physical address meeting
2225	  above alignment restrictions.
2226
2227	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2228	  this value must be a multiple of 0x200000.
2229
2230	  Don't change this unless you know what you are doing.
2231
2232config DYNAMIC_MEMORY_LAYOUT
2233	bool
2234	help
2235	  This option makes base addresses of vmalloc and vmemmap as well as
2236	  __PAGE_OFFSET movable during boot.
2237
2238config RANDOMIZE_MEMORY
2239	bool "Randomize the kernel memory sections"
2240	depends on X86_64
2241	depends on RANDOMIZE_BASE
2242	select DYNAMIC_MEMORY_LAYOUT
2243	default RANDOMIZE_BASE
2244	help
2245	  Randomizes the base virtual address of kernel memory sections
2246	  (physical memory mapping, vmalloc & vmemmap). This security feature
2247	  makes exploits relying on predictable memory locations less reliable.
2248
2249	  The order of allocations remains unchanged. Entropy is generated in
2250	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2251	  configuration have in average 30,000 different possible virtual
2252	  addresses for each memory section.
2253
2254	  If unsure, say Y.
2255
2256config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2257	hex "Physical memory mapping padding" if EXPERT
2258	depends on RANDOMIZE_MEMORY
2259	default "0xa" if MEMORY_HOTPLUG
2260	default "0x0"
2261	range 0x1 0x40 if MEMORY_HOTPLUG
2262	range 0x0 0x40
2263	help
2264	  Define the padding in terabytes added to the existing physical
2265	  memory size during kernel memory randomization. It is useful
2266	  for memory hotplug support but reduces the entropy available for
2267	  address randomization.
2268
2269	  If unsure, leave at the default value.
2270
2271config ADDRESS_MASKING
2272	bool "Linear Address Masking support"
2273	depends on X86_64
2274	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2275	help
2276	  Linear Address Masking (LAM) modifies the checking that is applied
2277	  to 64-bit linear addresses, allowing software to use of the
2278	  untranslated address bits for metadata.
2279
2280	  The capability can be used for efficient address sanitizers (ASAN)
2281	  implementation and for optimizations in JITs.
2282
2283config HOTPLUG_CPU
2284	def_bool y
2285	depends on SMP
2286
2287config COMPAT_VDSO
2288	def_bool n
2289	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2290	depends on COMPAT_32
2291	help
2292	  Certain buggy versions of glibc will crash if they are
2293	  presented with a 32-bit vDSO that is not mapped at the address
2294	  indicated in its segment table.
2295
2296	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2297	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2298	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2299	  the only released version with the bug, but OpenSUSE 9
2300	  contains a buggy "glibc 2.3.2".
2301
2302	  The symptom of the bug is that everything crashes on startup, saying:
2303	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2304
2305	  Saying Y here changes the default value of the vdso32 boot
2306	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2307	  This works around the glibc bug but hurts performance.
2308
2309	  If unsure, say N: if you are compiling your own kernel, you
2310	  are unlikely to be using a buggy version of glibc.
2311
2312choice
2313	prompt "vsyscall table for legacy applications"
2314	depends on X86_64
2315	default LEGACY_VSYSCALL_XONLY
2316	help
2317	  Legacy user code that does not know how to find the vDSO expects
2318	  to be able to issue three syscalls by calling fixed addresses in
2319	  kernel space. Since this location is not randomized with ASLR,
2320	  it can be used to assist security vulnerability exploitation.
2321
2322	  This setting can be changed at boot time via the kernel command
2323	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2324	  is deprecated and can only be enabled using the kernel command
2325	  line.
2326
2327	  On a system with recent enough glibc (2.14 or newer) and no
2328	  static binaries, you can say None without a performance penalty
2329	  to improve security.
2330
2331	  If unsure, select "Emulate execution only".
2332
2333	config LEGACY_VSYSCALL_XONLY
2334		bool "Emulate execution only"
2335		help
2336		  The kernel traps and emulates calls into the fixed vsyscall
2337		  address mapping and does not allow reads.  This
2338		  configuration is recommended when userspace might use the
2339		  legacy vsyscall area but support for legacy binary
2340		  instrumentation of legacy code is not needed.  It mitigates
2341		  certain uses of the vsyscall area as an ASLR-bypassing
2342		  buffer.
2343
2344	config LEGACY_VSYSCALL_NONE
2345		bool "None"
2346		help
2347		  There will be no vsyscall mapping at all. This will
2348		  eliminate any risk of ASLR bypass due to the vsyscall
2349		  fixed address mapping. Attempts to use the vsyscalls
2350		  will be reported to dmesg, so that either old or
2351		  malicious userspace programs can be identified.
2352
2353endchoice
2354
2355config CMDLINE_BOOL
2356	bool "Built-in kernel command line"
2357	help
2358	  Allow for specifying boot arguments to the kernel at
2359	  build time.  On some systems (e.g. embedded ones), it is
2360	  necessary or convenient to provide some or all of the
2361	  kernel boot arguments with the kernel itself (that is,
2362	  to not rely on the boot loader to provide them.)
2363
2364	  To compile command line arguments into the kernel,
2365	  set this option to 'Y', then fill in the
2366	  boot arguments in CONFIG_CMDLINE.
2367
2368	  Systems with fully functional boot loaders (i.e. non-embedded)
2369	  should leave this option set to 'N'.
2370
2371config CMDLINE
2372	string "Built-in kernel command string"
2373	depends on CMDLINE_BOOL
2374	default ""
2375	help
2376	  Enter arguments here that should be compiled into the kernel
2377	  image and used at boot time.  If the boot loader provides a
2378	  command line at boot time, it is appended to this string to
2379	  form the full kernel command line, when the system boots.
2380
2381	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2382	  change this behavior.
2383
2384	  In most cases, the command line (whether built-in or provided
2385	  by the boot loader) should specify the device for the root
2386	  file system.
2387
2388config CMDLINE_OVERRIDE
2389	bool "Built-in command line overrides boot loader arguments"
2390	depends on CMDLINE_BOOL && CMDLINE != ""
2391	help
2392	  Set this option to 'Y' to have the kernel ignore the boot loader
2393	  command line, and use ONLY the built-in command line.
2394
2395	  This is used to work around broken boot loaders.  This should
2396	  be set to 'N' under normal conditions.
2397
2398config MODIFY_LDT_SYSCALL
2399	bool "Enable the LDT (local descriptor table)" if EXPERT
2400	default y
2401	help
2402	  Linux can allow user programs to install a per-process x86
2403	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2404	  call.  This is required to run 16-bit or segmented code such as
2405	  DOSEMU or some Wine programs.  It is also used by some very old
2406	  threading libraries.
2407
2408	  Enabling this feature adds a small amount of overhead to
2409	  context switches and increases the low-level kernel attack
2410	  surface.  Disabling it removes the modify_ldt(2) system call.
2411
2412	  Saying 'N' here may make sense for embedded or server kernels.
2413
2414config STRICT_SIGALTSTACK_SIZE
2415	bool "Enforce strict size checking for sigaltstack"
2416	depends on DYNAMIC_SIGFRAME
2417	help
2418	  For historical reasons MINSIGSTKSZ is a constant which became
2419	  already too small with AVX512 support. Add a mechanism to
2420	  enforce strict checking of the sigaltstack size against the
2421	  real size of the FPU frame. This option enables the check
2422	  by default. It can also be controlled via the kernel command
2423	  line option 'strict_sas_size' independent of this config
2424	  switch. Enabling it might break existing applications which
2425	  allocate a too small sigaltstack but 'work' because they
2426	  never get a signal delivered.
2427
2428	  Say 'N' unless you want to really enforce this check.
2429
2430config CFI_AUTO_DEFAULT
2431	bool "Attempt to use FineIBT by default at boot time"
2432	depends on FINEIBT
2433	default y
2434	help
2435	  Attempt to use FineIBT by default at boot time. If enabled,
2436	  this is the same as booting with "cfi=auto". If disabled,
2437	  this is the same as booting with "cfi=kcfi".
2438
2439source "kernel/livepatch/Kconfig"
2440
2441config X86_BUS_LOCK_DETECT
2442	bool "Split Lock Detect and Bus Lock Detect support"
2443	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2444	default y
2445	help
2446	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2447	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2448
2449endmenu
2450
2451config CC_HAS_NAMED_AS
2452	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2453	depends on CC_IS_GCC
2454
2455config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2456	def_bool CC_IS_GCC && GCC_VERSION >= 130300
2457
2458config USE_X86_SEG_SUPPORT
2459	def_bool y
2460	depends on CC_HAS_NAMED_AS
2461	#
2462	# -fsanitize=kernel-address (KASAN) and -fsanitize=thread
2463	# (KCSAN) are incompatible with named address spaces with
2464	# GCC < 13.3 - see GCC PR sanitizer/111736.
2465	#
2466	depends on !(KASAN || KCSAN) || CC_HAS_NAMED_AS_FIXED_SANITIZERS
2467
2468config CC_HAS_SLS
2469	def_bool $(cc-option,-mharden-sls=all)
2470
2471config CC_HAS_RETURN_THUNK
2472	def_bool $(cc-option,-mfunction-return=thunk-extern)
2473
2474config CC_HAS_ENTRY_PADDING
2475	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2476
2477config FUNCTION_PADDING_CFI
2478	int
2479	default 59 if FUNCTION_ALIGNMENT_64B
2480	default 27 if FUNCTION_ALIGNMENT_32B
2481	default 11 if FUNCTION_ALIGNMENT_16B
2482	default  3 if FUNCTION_ALIGNMENT_8B
2483	default  0
2484
2485# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2486# except Kconfig can't do arithmetic :/
2487config FUNCTION_PADDING_BYTES
2488	int
2489	default FUNCTION_PADDING_CFI if CFI_CLANG
2490	default FUNCTION_ALIGNMENT
2491
2492config CALL_PADDING
2493	def_bool n
2494	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2495	select FUNCTION_ALIGNMENT_16B
2496
2497config FINEIBT
2498	def_bool y
2499	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2500	select CALL_PADDING
2501
2502config HAVE_CALL_THUNKS
2503	def_bool y
2504	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2505
2506config CALL_THUNKS
2507	def_bool n
2508	select CALL_PADDING
2509
2510config PREFIX_SYMBOLS
2511	def_bool y
2512	depends on CALL_PADDING && !CFI_CLANG
2513
2514menuconfig CPU_MITIGATIONS
2515	bool "Mitigations for CPU vulnerabilities"
2516	default y
2517	help
2518	  Say Y here to enable options which enable mitigations for hardware
2519	  vulnerabilities (usually related to speculative execution).
2520	  Mitigations can be disabled or restricted to SMT systems at runtime
2521	  via the "mitigations" kernel parameter.
2522
2523	  If you say N, all mitigations will be disabled.  This CANNOT be
2524	  overridden at runtime.
2525
2526	  Say 'Y', unless you really know what you are doing.
2527
2528if CPU_MITIGATIONS
2529
2530config MITIGATION_PAGE_TABLE_ISOLATION
2531	bool "Remove the kernel mapping in user mode"
2532	default y
2533	depends on (X86_64 || X86_PAE)
2534	help
2535	  This feature reduces the number of hardware side channels by
2536	  ensuring that the majority of kernel addresses are not mapped
2537	  into userspace.
2538
2539	  See Documentation/arch/x86/pti.rst for more details.
2540
2541config MITIGATION_RETPOLINE
2542	bool "Avoid speculative indirect branches in kernel"
2543	select OBJTOOL if HAVE_OBJTOOL
2544	default y
2545	help
2546	  Compile kernel with the retpoline compiler options to guard against
2547	  kernel-to-user data leaks by avoiding speculative indirect
2548	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2549	  support for full protection. The kernel may run slower.
2550
2551config MITIGATION_RETHUNK
2552	bool "Enable return-thunks"
2553	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2554	select OBJTOOL if HAVE_OBJTOOL
2555	default y if X86_64
2556	help
2557	  Compile the kernel with the return-thunks compiler option to guard
2558	  against kernel-to-user data leaks by avoiding return speculation.
2559	  Requires a compiler with -mfunction-return=thunk-extern
2560	  support for full protection. The kernel may run slower.
2561
2562config MITIGATION_UNRET_ENTRY
2563	bool "Enable UNRET on kernel entry"
2564	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2565	default y
2566	help
2567	  Compile the kernel with support for the retbleed=unret mitigation.
2568
2569config MITIGATION_CALL_DEPTH_TRACKING
2570	bool "Mitigate RSB underflow with call depth tracking"
2571	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2572	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2573	select CALL_THUNKS
2574	default y
2575	help
2576	  Compile the kernel with call depth tracking to mitigate the Intel
2577	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2578	  by default and needs to be enabled on the kernel command line via the
2579	  retbleed=stuff option. For non-affected systems the overhead of this
2580	  option is marginal as the call depth tracking is using run-time
2581	  generated call thunks in a compiler generated padding area and call
2582	  patching. This increases text size by ~5%. For non affected systems
2583	  this space is unused. On affected SKL systems this results in a
2584	  significant performance gain over the IBRS mitigation.
2585
2586config CALL_THUNKS_DEBUG
2587	bool "Enable call thunks and call depth tracking debugging"
2588	depends on MITIGATION_CALL_DEPTH_TRACKING
2589	select FUNCTION_ALIGNMENT_32B
2590	default n
2591	help
2592	  Enable call/ret counters for imbalance detection and build in
2593	  a noisy dmesg about callthunks generation and call patching for
2594	  trouble shooting. The debug prints need to be enabled on the
2595	  kernel command line with 'debug-callthunks'.
2596	  Only enable this when you are debugging call thunks as this
2597	  creates a noticeable runtime overhead. If unsure say N.
2598
2599config MITIGATION_IBPB_ENTRY
2600	bool "Enable IBPB on kernel entry"
2601	depends on CPU_SUP_AMD && X86_64
2602	default y
2603	help
2604	  Compile the kernel with support for the retbleed=ibpb and
2605	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2606
2607config MITIGATION_IBRS_ENTRY
2608	bool "Enable IBRS on kernel entry"
2609	depends on CPU_SUP_INTEL && X86_64
2610	default y
2611	help
2612	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2613	  This mitigates both spectre_v2 and retbleed at great cost to
2614	  performance.
2615
2616config MITIGATION_SRSO
2617	bool "Mitigate speculative RAS overflow on AMD"
2618	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2619	default y
2620	help
2621	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2622
2623config MITIGATION_SLS
2624	bool "Mitigate Straight-Line-Speculation"
2625	depends on CC_HAS_SLS && X86_64
2626	select OBJTOOL if HAVE_OBJTOOL
2627	default n
2628	help
2629	  Compile the kernel with straight-line-speculation options to guard
2630	  against straight line speculation. The kernel image might be slightly
2631	  larger.
2632
2633config MITIGATION_GDS
2634	bool "Mitigate Gather Data Sampling"
2635	depends on CPU_SUP_INTEL
2636	default y
2637	help
2638	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2639	  vulnerability which allows unprivileged speculative access to data
2640	  which was previously stored in vector registers. The attacker uses gather
2641	  instructions to infer the stale vector register data.
2642
2643config MITIGATION_RFDS
2644	bool "RFDS Mitigation"
2645	depends on CPU_SUP_INTEL
2646	default y
2647	help
2648	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2649	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2650	  allows unprivileged speculative access to stale data previously
2651	  stored in floating point, vector and integer registers.
2652	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2653
2654config MITIGATION_SPECTRE_BHI
2655	bool "Mitigate Spectre-BHB (Branch History Injection)"
2656	depends on CPU_SUP_INTEL
2657	default y
2658	help
2659	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2660	  where the branch history buffer is poisoned to speculatively steer
2661	  indirect branches.
2662	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2663
2664config MITIGATION_MDS
2665	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2666	depends on CPU_SUP_INTEL
2667	default y
2668	help
2669	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2670	  a hardware vulnerability which allows unprivileged speculative access
2671	  to data which is available in various CPU internal buffers.
2672	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2673
2674config MITIGATION_TAA
2675	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2676	depends on CPU_SUP_INTEL
2677	default y
2678	help
2679	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2680	  vulnerability that allows unprivileged speculative access to data
2681	  which is available in various CPU internal buffers by using
2682	  asynchronous aborts within an Intel TSX transactional region.
2683	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2684
2685config MITIGATION_MMIO_STALE_DATA
2686	bool "Mitigate MMIO Stale Data hardware bug"
2687	depends on CPU_SUP_INTEL
2688	default y
2689	help
2690	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2691	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2692	  vulnerabilities that can expose data. The vulnerabilities require the
2693	  attacker to have access to MMIO.
2694	  See also
2695	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2696
2697config MITIGATION_L1TF
2698	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2699	depends on CPU_SUP_INTEL
2700	default y
2701	help
2702	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2703	  hardware vulnerability which allows unprivileged speculative access to data
2704	  available in the Level 1 Data Cache.
2705	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2706
2707config MITIGATION_RETBLEED
2708	bool "Mitigate RETBleed hardware bug"
2709	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2710	default y
2711	help
2712	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2713	  with Return Instructions) vulnerability.  RETBleed is a speculative
2714	  execution attack which takes advantage of microarchitectural behavior
2715	  in many modern microprocessors, similar to Spectre v2. An
2716	  unprivileged attacker can use these flaws to bypass conventional
2717	  memory security restrictions to gain read access to privileged memory
2718	  that would otherwise be inaccessible.
2719
2720config MITIGATION_SPECTRE_V1
2721	bool "Mitigate SPECTRE V1 hardware bug"
2722	default y
2723	help
2724	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2725	  class of side channel attacks that takes advantage of speculative
2726	  execution that bypasses conditional branch instructions used for
2727	  memory access bounds check.
2728	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2729
2730config MITIGATION_SPECTRE_V2
2731	bool "Mitigate SPECTRE V2 hardware bug"
2732	default y
2733	help
2734	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2735	  V2 is a class of side channel attacks that takes advantage of
2736	  indirect branch predictors inside the processor. In Spectre variant 2
2737	  attacks, the attacker can steer speculative indirect branches in the
2738	  victim to gadget code by poisoning the branch target buffer of a CPU
2739	  used for predicting indirect branch addresses.
2740	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2741
2742config MITIGATION_SRBDS
2743	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2744	depends on CPU_SUP_INTEL
2745	default y
2746	help
2747	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2748	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2749	  Sampling (MDS) techniques to infer values returned from special
2750	  register accesses. An unprivileged user can extract values returned
2751	  from RDRAND and RDSEED executed on another core or sibling thread
2752	  using MDS techniques.
2753	  See also
2754	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2755
2756config MITIGATION_SSB
2757	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2758	default y
2759	help
2760	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2761	  hardware security vulnerability and its exploitation takes advantage
2762	  of speculative execution in a similar way to the Meltdown and Spectre
2763	  security vulnerabilities.
2764
2765endif
2766
2767config ARCH_HAS_ADD_PAGES
2768	def_bool y
2769	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2770
2771menu "Power management and ACPI options"
2772
2773config ARCH_HIBERNATION_HEADER
2774	def_bool y
2775	depends on HIBERNATION
2776
2777source "kernel/power/Kconfig"
2778
2779source "drivers/acpi/Kconfig"
2780
2781config X86_APM_BOOT
2782	def_bool y
2783	depends on APM
2784
2785menuconfig APM
2786	tristate "APM (Advanced Power Management) BIOS support"
2787	depends on X86_32 && PM_SLEEP
2788	help
2789	  APM is a BIOS specification for saving power using several different
2790	  techniques. This is mostly useful for battery powered laptops with
2791	  APM compliant BIOSes. If you say Y here, the system time will be
2792	  reset after a RESUME operation, the /proc/apm device will provide
2793	  battery status information, and user-space programs will receive
2794	  notification of APM "events" (e.g. battery status change).
2795
2796	  If you select "Y" here, you can disable actual use of the APM
2797	  BIOS by passing the "apm=off" option to the kernel at boot time.
2798
2799	  Note that the APM support is almost completely disabled for
2800	  machines with more than one CPU.
2801
2802	  In order to use APM, you will need supporting software. For location
2803	  and more information, read <file:Documentation/power/apm-acpi.rst>
2804	  and the Battery Powered Linux mini-HOWTO, available from
2805	  <http://www.tldp.org/docs.html#howto>.
2806
2807	  This driver does not spin down disk drives (see the hdparm(8)
2808	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2809	  VESA-compliant "green" monitors.
2810
2811	  This driver does not support the TI 4000M TravelMate and the ACER
2812	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2813	  desktop machines also don't have compliant BIOSes, and this driver
2814	  may cause those machines to panic during the boot phase.
2815
2816	  Generally, if you don't have a battery in your machine, there isn't
2817	  much point in using this driver and you should say N. If you get
2818	  random kernel OOPSes or reboots that don't seem to be related to
2819	  anything, try disabling/enabling this option (or disabling/enabling
2820	  APM in your BIOS).
2821
2822	  Some other things you should try when experiencing seemingly random,
2823	  "weird" problems:
2824
2825	  1) make sure that you have enough swap space and that it is
2826	  enabled.
2827	  2) pass the "idle=poll" option to the kernel
2828	  3) switch on floating point emulation in the kernel and pass
2829	  the "no387" option to the kernel
2830	  4) pass the "floppy=nodma" option to the kernel
2831	  5) pass the "mem=4M" option to the kernel (thereby disabling
2832	  all but the first 4 MB of RAM)
2833	  6) make sure that the CPU is not over clocked.
2834	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2835	  8) disable the cache from your BIOS settings
2836	  9) install a fan for the video card or exchange video RAM
2837	  10) install a better fan for the CPU
2838	  11) exchange RAM chips
2839	  12) exchange the motherboard.
2840
2841	  To compile this driver as a module, choose M here: the
2842	  module will be called apm.
2843
2844if APM
2845
2846config APM_IGNORE_USER_SUSPEND
2847	bool "Ignore USER SUSPEND"
2848	help
2849	  This option will ignore USER SUSPEND requests. On machines with a
2850	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2851	  series notebooks, it is necessary to say Y because of a BIOS bug.
2852
2853config APM_DO_ENABLE
2854	bool "Enable PM at boot time"
2855	help
2856	  Enable APM features at boot time. From page 36 of the APM BIOS
2857	  specification: "When disabled, the APM BIOS does not automatically
2858	  power manage devices, enter the Standby State, enter the Suspend
2859	  State, or take power saving steps in response to CPU Idle calls."
2860	  This driver will make CPU Idle calls when Linux is idle (unless this
2861	  feature is turned off -- see "Do CPU IDLE calls", below). This
2862	  should always save battery power, but more complicated APM features
2863	  will be dependent on your BIOS implementation. You may need to turn
2864	  this option off if your computer hangs at boot time when using APM
2865	  support, or if it beeps continuously instead of suspending. Turn
2866	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2867	  T400CDT. This is off by default since most machines do fine without
2868	  this feature.
2869
2870config APM_CPU_IDLE
2871	depends on CPU_IDLE
2872	bool "Make CPU Idle calls when idle"
2873	help
2874	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2875	  On some machines, this can activate improved power savings, such as
2876	  a slowed CPU clock rate, when the machine is idle. These idle calls
2877	  are made after the idle loop has run for some length of time (e.g.,
2878	  333 mS). On some machines, this will cause a hang at boot time or
2879	  whenever the CPU becomes idle. (On machines with more than one CPU,
2880	  this option does nothing.)
2881
2882config APM_DISPLAY_BLANK
2883	bool "Enable console blanking using APM"
2884	help
2885	  Enable console blanking using the APM. Some laptops can use this to
2886	  turn off the LCD backlight when the screen blanker of the Linux
2887	  virtual console blanks the screen. Note that this is only used by
2888	  the virtual console screen blanker, and won't turn off the backlight
2889	  when using the X Window system. This also doesn't have anything to
2890	  do with your VESA-compliant power-saving monitor. Further, this
2891	  option doesn't work for all laptops -- it might not turn off your
2892	  backlight at all, or it might print a lot of errors to the console,
2893	  especially if you are using gpm.
2894
2895config APM_ALLOW_INTS
2896	bool "Allow interrupts during APM BIOS calls"
2897	help
2898	  Normally we disable external interrupts while we are making calls to
2899	  the APM BIOS as a measure to lessen the effects of a badly behaving
2900	  BIOS implementation.  The BIOS should reenable interrupts if it
2901	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2902	  many of the newer IBM Thinkpads.  If you experience hangs when you
2903	  suspend, try setting this to Y.  Otherwise, say N.
2904
2905endif # APM
2906
2907source "drivers/cpufreq/Kconfig"
2908
2909source "drivers/cpuidle/Kconfig"
2910
2911source "drivers/idle/Kconfig"
2912
2913endmenu
2914
2915menu "Bus options (PCI etc.)"
2916
2917choice
2918	prompt "PCI access mode"
2919	depends on X86_32 && PCI
2920	default PCI_GOANY
2921	help
2922	  On PCI systems, the BIOS can be used to detect the PCI devices and
2923	  determine their configuration. However, some old PCI motherboards
2924	  have BIOS bugs and may crash if this is done. Also, some embedded
2925	  PCI-based systems don't have any BIOS at all. Linux can also try to
2926	  detect the PCI hardware directly without using the BIOS.
2927
2928	  With this option, you can specify how Linux should detect the
2929	  PCI devices. If you choose "BIOS", the BIOS will be used,
2930	  if you choose "Direct", the BIOS won't be used, and if you
2931	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2932	  If you choose "Any", the kernel will try MMCONFIG, then the
2933	  direct access method and falls back to the BIOS if that doesn't
2934	  work. If unsure, go with the default, which is "Any".
2935
2936config PCI_GOBIOS
2937	bool "BIOS"
2938
2939config PCI_GOMMCONFIG
2940	bool "MMConfig"
2941
2942config PCI_GODIRECT
2943	bool "Direct"
2944
2945config PCI_GOOLPC
2946	bool "OLPC XO-1"
2947	depends on OLPC
2948
2949config PCI_GOANY
2950	bool "Any"
2951
2952endchoice
2953
2954config PCI_BIOS
2955	def_bool y
2956	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2957
2958# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2959config PCI_DIRECT
2960	def_bool y
2961	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2962
2963config PCI_MMCONFIG
2964	bool "Support mmconfig PCI config space access" if X86_64
2965	default y
2966	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2967	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2968
2969config PCI_OLPC
2970	def_bool y
2971	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2972
2973config PCI_XEN
2974	def_bool y
2975	depends on PCI && XEN
2976
2977config MMCONF_FAM10H
2978	def_bool y
2979	depends on X86_64 && PCI_MMCONFIG && ACPI
2980
2981config PCI_CNB20LE_QUIRK
2982	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2983	depends on PCI
2984	help
2985	  Read the PCI windows out of the CNB20LE host bridge. This allows
2986	  PCI hotplug to work on systems with the CNB20LE chipset which do
2987	  not have ACPI.
2988
2989	  There's no public spec for this chipset, and this functionality
2990	  is known to be incomplete.
2991
2992	  You should say N unless you know you need this.
2993
2994config ISA_BUS
2995	bool "ISA bus support on modern systems" if EXPERT
2996	help
2997	  Expose ISA bus device drivers and options available for selection and
2998	  configuration. Enable this option if your target machine has an ISA
2999	  bus. ISA is an older system, displaced by PCI and newer bus
3000	  architectures -- if your target machine is modern, it probably does
3001	  not have an ISA bus.
3002
3003	  If unsure, say N.
3004
3005# x86_64 have no ISA slots, but can have ISA-style DMA.
3006config ISA_DMA_API
3007	bool "ISA-style DMA support" if (X86_64 && EXPERT)
3008	default y
3009	help
3010	  Enables ISA-style DMA support for devices requiring such controllers.
3011	  If unsure, say Y.
3012
3013if X86_32
3014
3015config ISA
3016	bool "ISA support"
3017	help
3018	  Find out whether you have ISA slots on your motherboard.  ISA is the
3019	  name of a bus system, i.e. the way the CPU talks to the other stuff
3020	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
3021	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
3022	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
3023
3024config SCx200
3025	tristate "NatSemi SCx200 support"
3026	help
3027	  This provides basic support for National Semiconductor's
3028	  (now AMD's) Geode processors.  The driver probes for the
3029	  PCI-IDs of several on-chip devices, so its a good dependency
3030	  for other scx200_* drivers.
3031
3032	  If compiled as a module, the driver is named scx200.
3033
3034config SCx200HR_TIMER
3035	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
3036	depends on SCx200
3037	default y
3038	help
3039	  This driver provides a clocksource built upon the on-chip
3040	  27MHz high-resolution timer.  Its also a workaround for
3041	  NSC Geode SC-1100's buggy TSC, which loses time when the
3042	  processor goes idle (as is done by the scheduler).  The
3043	  other workaround is idle=poll boot option.
3044
3045config OLPC
3046	bool "One Laptop Per Child support"
3047	depends on !X86_PAE
3048	select GPIOLIB
3049	select OF
3050	select OF_PROMTREE
3051	select IRQ_DOMAIN
3052	select OLPC_EC
3053	help
3054	  Add support for detecting the unique features of the OLPC
3055	  XO hardware.
3056
3057config OLPC_XO1_PM
3058	bool "OLPC XO-1 Power Management"
3059	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3060	help
3061	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3062
3063config OLPC_XO1_RTC
3064	bool "OLPC XO-1 Real Time Clock"
3065	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3066	help
3067	  Add support for the XO-1 real time clock, which can be used as a
3068	  programmable wakeup source.
3069
3070config OLPC_XO1_SCI
3071	bool "OLPC XO-1 SCI extras"
3072	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3073	depends on INPUT=y
3074	select POWER_SUPPLY
3075	help
3076	  Add support for SCI-based features of the OLPC XO-1 laptop:
3077	   - EC-driven system wakeups
3078	   - Power button
3079	   - Ebook switch
3080	   - Lid switch
3081	   - AC adapter status updates
3082	   - Battery status updates
3083
3084config OLPC_XO15_SCI
3085	bool "OLPC XO-1.5 SCI extras"
3086	depends on OLPC && ACPI
3087	select POWER_SUPPLY
3088	help
3089	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3090	   - EC-driven system wakeups
3091	   - AC adapter status updates
3092	   - Battery status updates
3093
3094config GEODE_COMMON
3095	bool
3096
3097config ALIX
3098	bool "PCEngines ALIX System Support (LED setup)"
3099	select GPIOLIB
3100	select GEODE_COMMON
3101	help
3102	  This option enables system support for the PCEngines ALIX.
3103	  At present this just sets up LEDs for GPIO control on
3104	  ALIX2/3/6 boards.  However, other system specific setup should
3105	  get added here.
3106
3107	  Note: You must still enable the drivers for GPIO and LED support
3108	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3109
3110	  Note: You have to set alix.force=1 for boards with Award BIOS.
3111
3112config NET5501
3113	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3114	select GPIOLIB
3115	select GEODE_COMMON
3116	help
3117	  This option enables system support for the Soekris Engineering net5501.
3118
3119config GEOS
3120	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3121	select GPIOLIB
3122	select GEODE_COMMON
3123	depends on DMI
3124	help
3125	  This option enables system support for the Traverse Technologies GEOS.
3126
3127config TS5500
3128	bool "Technologic Systems TS-5500 platform support"
3129	depends on MELAN
3130	select CHECK_SIGNATURE
3131	select NEW_LEDS
3132	select LEDS_CLASS
3133	help
3134	  This option enables system support for the Technologic Systems TS-5500.
3135
3136endif # X86_32
3137
3138config AMD_NB
3139	def_bool y
3140	depends on AMD_NODE
3141
3142config AMD_NODE
3143	def_bool y
3144	depends on CPU_SUP_AMD && PCI
3145
3146endmenu
3147
3148menu "Binary Emulations"
3149
3150config IA32_EMULATION
3151	bool "IA32 Emulation"
3152	depends on X86_64
3153	select ARCH_WANT_OLD_COMPAT_IPC
3154	select BINFMT_ELF
3155	select COMPAT_OLD_SIGACTION
3156	help
3157	  Include code to run legacy 32-bit programs under a
3158	  64-bit kernel. You should likely turn this on, unless you're
3159	  100% sure that you don't have any 32-bit programs left.
3160
3161config IA32_EMULATION_DEFAULT_DISABLED
3162	bool "IA32 emulation disabled by default"
3163	default n
3164	depends on IA32_EMULATION
3165	help
3166	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3167	  processes and access to 32-bit syscalls. If unsure, leave it to its
3168	  default value.
3169
3170config X86_X32_ABI
3171	bool "x32 ABI for 64-bit mode"
3172	depends on X86_64
3173	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3174	# compressed debug sections to x86_x32 properly:
3175	# https://github.com/ClangBuiltLinux/linux/issues/514
3176	# https://github.com/ClangBuiltLinux/linux/issues/1141
3177	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3178	help
3179	  Include code to run binaries for the x32 native 32-bit ABI
3180	  for 64-bit processors.  An x32 process gets access to the
3181	  full 64-bit register file and wide data path while leaving
3182	  pointers at 32 bits for smaller memory footprint.
3183
3184config COMPAT_32
3185	def_bool y
3186	depends on IA32_EMULATION || X86_32
3187	select HAVE_UID16
3188	select OLD_SIGSUSPEND3
3189
3190config COMPAT
3191	def_bool y
3192	depends on IA32_EMULATION || X86_X32_ABI
3193
3194config COMPAT_FOR_U64_ALIGNMENT
3195	def_bool y
3196	depends on COMPAT
3197
3198endmenu
3199
3200config HAVE_ATOMIC_IOMAP
3201	def_bool y
3202	depends on X86_32
3203
3204source "arch/x86/kvm/Kconfig"
3205
3206source "arch/x86/Kconfig.assembler"
3207