xref: /linux/arch/x86/Kconfig (revision 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select HAVE_DEBUG_STACKOVERFLOW
18	select KMAP_LOCAL
19	select MODULES_USE_ELF_REL
20	select OLD_SIGACTION
21	select ARCH_SPLIT_ARG64
22
23config X86_64
24	def_bool y
25	depends on 64BIT
26	# Options that are inherently 64-bit kernel only:
27	select ARCH_HAS_GIGANTIC_PAGE
28	select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
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	select ACPI_MRRM if ACPI
40
41config FORCE_DYNAMIC_FTRACE
42	def_bool y
43	depends on X86_32
44	depends on FUNCTION_TRACER
45	select DYNAMIC_FTRACE
46	help
47	  We keep the static function tracing (!DYNAMIC_FTRACE) around
48	  in order to test the non static function tracing in the
49	  generic code, as other architectures still use it. But we
50	  only need to keep it around for x86_64. No need to keep it
51	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
52#
53# Arch settings
54#
55# ( Note that options that are marked 'if X86_64' could in principle be
56#   ported to 32-bit as well. )
57#
58config X86
59	def_bool y
60	#
61	# Note: keep this list sorted alphabetically
62	#
63	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
64	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
65	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
66	select ARCH_32BIT_OFF_T			if X86_32
67	select ARCH_CLOCKSOURCE_INIT
68	select ARCH_CONFIGURES_CPU_MITIGATIONS
69	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
70	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
71	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
72	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
73	select ARCH_HAS_PMD_SOFTLEAVES if X86_64 && TRANSPARENT_HUGEPAGE
74	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
75	select ARCH_HAS_CPU_ATTACK_VECTORS	if CPU_MITIGATIONS
76	select ARCH_HAS_CACHE_LINE_SIZE
77	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
78	select ARCH_HAS_CPU_FINALIZE_INIT
79	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
80	select ARCH_HAS_CURRENT_STACK_POINTER
81	select ARCH_HAS_DEBUG_VIRTUAL
82	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
83	select ARCH_HAS_DELAY_TIMER
84	select ARCH_HAS_DEVMEM_IS_ALLOWED
85	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
86	select ARCH_HAS_EARLY_DEBUG		if KGDB
87	select ARCH_HAS_ELF_RANDOMIZE
88	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
89	select ARCH_HAS_FAST_MULTIPLIER
90	select ARCH_HAS_FORTIFY_SOURCE
91	select ARCH_HAS_GCOV_PROFILE_ALL
92	select ARCH_HAS_KCOV			if X86_64
93	select ARCH_HAS_KERNEL_FPU_SUPPORT
94	select ARCH_HAS_MEM_ENCRYPT
95	select ARCH_HAS_MEMBARRIER_SYNC_CORE
96	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
97	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
98	select ARCH_HAS_PMEM_API		if X86_64
99	select ARCH_HAS_PREEMPT_LAZY
100	select ARCH_HAS_PTDUMP
101	select ARCH_HAS_PTE_SPECIAL
102	select ARCH_HAS_HW_PTE_YOUNG
103	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
104	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
105	select ARCH_HAS_COPY_MC			if X86_64
106	select ARCH_HAS_SET_MEMORY
107	select ARCH_HAS_SET_DIRECT_MAP
108	select ARCH_HAS_STRICT_KERNEL_RWX
109	select ARCH_HAS_STRICT_MODULE_RWX
110	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
111	select ARCH_HAS_SYSCALL_WRAPPER
112	select ARCH_HAS_UBSAN
113	select ARCH_HAS_DEBUG_WX
114	select ARCH_HAS_ZONE_DMA_SET if EXPERT
115	select ARCH_HAVE_NMI_SAFE_CMPXCHG
116	select ARCH_HAVE_EXTRA_ELF_NOTES
117	select ARCH_MEMORY_ORDER_TSO
118	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
119	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
120	select ARCH_MIGHT_HAVE_PC_PARPORT
121	select ARCH_MIGHT_HAVE_PC_SERIO
122	select ARCH_STACKWALK
123	select ARCH_SUPPORTS_ACPI
124	select ARCH_SUPPORTS_ATOMIC_RMW
125	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
126	select ARCH_SUPPORTS_HUGETLBFS
127	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
128	select ARCH_HAS_PTE_PROTNONE		if X86_64
129	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
130	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
131	select ARCH_SUPPORTS_CFI		if X86_64
132	select ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG
133	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI
134	select ARCH_SUPPORTS_LTO_CLANG
135	select ARCH_SUPPORTS_LTO_CLANG_THIN
136	select ARCH_SUPPORTS_RT
137	select ARCH_USE_BUILTIN_BSWAP
138	select ARCH_USE_CMPXCHG_LOCKREF
139	select ARCH_USE_MEMTEST
140	select ARCH_USE_QUEUED_RWLOCKS
141	select ARCH_USE_QUEUED_SPINLOCKS
142	select ARCH_USE_SYM_ANNOTATIONS
143	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
144	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
145	select ARCH_WANTS_CLOCKSOURCE_READ_INLINE	if X86_64
146	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
147	select ARCH_WANTS_NO_INSTR
148	select ARCH_WANT_GENERAL_HUGETLB
149	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
150	select ARCH_WANT_LD_ORPHAN_WARN
151	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
152	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
153	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
154	select ARCH_WANTS_THP_SWAP		if X86_64
155	select ARCH_HAS_PARANOID_L1D_FLUSH
156	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
157	select BUILDTIME_TABLE_SORT
158	select CLKEVT_I8253
159	select CLOCKSOURCE_WATCHDOG
160	# Word-size accesses may read uninitialized data past the trailing \0
161	# in strings and cause false KMSAN reports.
162	select DCACHE_WORD_ACCESS		if !KMSAN
163	select DYNAMIC_SIGFRAME
164	select EDAC_ATOMIC_SCRUB
165	select EDAC_SUPPORT
166	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
167	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
168	select GENERIC_CLOCKEVENTS_COUPLED_INLINE	if X86_64
169	select GENERIC_CLOCKEVENTS_MIN_ADJUST
170	select GENERIC_CMOS_UPDATE
171	select GENERIC_CPU_AUTOPROBE
172	select GENERIC_CPU_DEVICES
173	select GENERIC_CPU_VULNERABILITIES
174	select GENERIC_EARLY_IOREMAP
175	select GENERIC_ENTRY
176	select GENERIC_IOMAP
177	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
178	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
179	select GENERIC_IRQ_MIGRATION		if SMP
180	select GENERIC_IRQ_PROBE
181	select GENERIC_IRQ_RESERVATION_MODE
182	select GENERIC_IRQ_SHOW
183	select GENERIC_PENDING_IRQ		if SMP
184	select GENERIC_SMP_IDLE_THREAD
185	select GENERIC_GETTIMEOFDAY
186	select GENERIC_VDSO_OVERFLOW_PROTECT
187	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
188	select HARDIRQS_SW_RESEND
189	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
190	select HAS_IOPORT
191	select HAVE_ACPI_APEI			if ACPI
192	select HAVE_ACPI_APEI_NMI		if ACPI
193	select HAVE_ALIGNED_STRUCT_PAGE
194	select HAVE_ARCH_AUDITSYSCALL
195	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
196	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
197	select HAVE_ARCH_JUMP_LABEL
198	select HAVE_ARCH_JUMP_LABEL_RELATIVE
199	select HAVE_ARCH_KASAN			if X86_64
200	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
201	select HAVE_ARCH_KFENCE
202	select HAVE_ARCH_KMSAN			if X86_64
203	select HAVE_ARCH_KGDB
204	select HAVE_ARCH_KSTACK_ERASE
205	select HAVE_ARCH_MMAP_RND_BITS		if MMU
206	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
207	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
208	select HAVE_ARCH_PREL32_RELOCATIONS
209	select HAVE_ARCH_SECCOMP_FILTER
210	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
211	select HAVE_ARCH_TRACEHOOK
212	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
213	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
214	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
215	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
216	select HAVE_ARCH_VMAP_STACK		if X86_64
217	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
218	select HAVE_ARCH_WITHIN_STACK_FRAMES
219	select HAVE_ASM_MODVERSIONS
220	select HAVE_CMPXCHG_DOUBLE
221	select HAVE_CMPXCHG_LOCAL
222	select HAVE_CONTEXT_TRACKING_USER		if X86_64
223	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
224	select HAVE_C_RECORDMCOUNT
225	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
226	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
227	select HAVE_BUILDTIME_MCOUNT_SORT
228	select HAVE_DEBUG_KMEMLEAK
229	select HAVE_DMA_CONTIGUOUS
230	select HAVE_DYNAMIC_FTRACE
231	select HAVE_DYNAMIC_FTRACE_WITH_REGS
232	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
233	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
234	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
235	select HAVE_DYNAMIC_FTRACE_WITH_JMP	if X86_64
236	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
237	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
238	select HAVE_EBPF_JIT
239	select HAVE_EFFICIENT_UNALIGNED_ACCESS
240	select HAVE_EISA			if X86_32
241	select HAVE_EXIT_THREAD
242	select HAVE_FUTEX_ROBUST_UNLOCK
243	select HAVE_GENERIC_TIF_BITS
244	select HAVE_GUP_FAST
245	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
246	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
247	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
248	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
249	select HAVE_FUNCTION_TRACER
250	select HAVE_GCC_PLUGINS
251	select HAVE_HW_BREAKPOINT
252	select HAVE_IOREMAP_PROT
253	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
254	select HAVE_IRQ_TIME_ACCOUNTING
255	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
256	select HAVE_KERNEL_BZIP2
257	select HAVE_KERNEL_GZIP
258	select HAVE_KERNEL_LZ4
259	select HAVE_KERNEL_LZMA
260	select HAVE_KERNEL_LZO
261	select HAVE_KERNEL_XZ
262	select HAVE_KERNEL_ZSTD
263	select HAVE_KPROBES
264	select HAVE_KPROBES_ON_FTRACE
265	select HAVE_FUNCTION_ERROR_INJECTION
266	select HAVE_KRETPROBES
267	select HAVE_RETHOOK
268	select HAVE_KLP_BUILD			if X86_64
269	select HAVE_LIVEPATCH			if X86_64
270	select HAVE_MIXED_BREAKPOINTS_REGS
271	select HAVE_MOD_ARCH_SPECIFIC
272	select HAVE_MOVE_PMD
273	select HAVE_MOVE_PUD
274	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
275	select HAVE_NMI
276	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
277	select HAVE_OBJTOOL			if X86_64
278	select HAVE_OPTPROBES
279	select HAVE_PAGE_SIZE_4KB
280	select HAVE_PCSPKR_PLATFORM
281	select HAVE_PERF_EVENTS
282	select HAVE_PERF_EVENTS_NMI
283	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
284	select HAVE_PCI
285	select HAVE_PERF_REGS
286	select HAVE_PERF_USER_STACK_DUMP
287	select ASYNC_KERNEL_PGTABLE_FREE	if IOMMU_SVA
288	select MMU_GATHER_RCU_TABLE_FREE
289	select MMU_GATHER_MERGE_VMAS
290	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
291	select HAVE_REGS_AND_STACK_ACCESS_API
292	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
293	select HAVE_FUNCTION_ARG_ACCESS_API
294	select HAVE_SETUP_PER_CPU_AREA
295	select HAVE_SOFTIRQ_ON_OWN_STACK
296	select HAVE_STACKPROTECTOR
297	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
298	select HAVE_STATIC_CALL
299	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
300	select HAVE_PREEMPT_DYNAMIC_CALL
301	select HAVE_RSEQ
302	select HAVE_RUST			if X86_64
303	select HAVE_SYSCALL_TRACEPOINTS
304	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
305	select HAVE_UNSTABLE_SCHED_CLOCK
306	select HAVE_UNWIND_USER_FP		if X86_64
307	select HAVE_USER_RETURN_NOTIFIER
308	select VDSO_GETRANDOM			if X86_64
309	select HOTPLUG_PARALLEL			if SMP && X86_64
310	select HOTPLUG_SMT			if SMP
311	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
312	select IRQ_FORCED_THREADING
313	select LOCK_MM_AND_FIND_VMA
314	select NEED_PER_CPU_EMBED_FIRST_CHUNK
315	select NEED_PER_CPU_PAGE_FIRST_CHUNK
316	select NEED_SG_DMA_LENGTH
317	select NUMA_MEMBLKS			if NUMA
318	select PCI_DOMAINS			if PCI
319	select PCI_LOCKLESS_CONFIG		if PCI
320	select PERF_EVENTS
321	select RTC_LIB
322	select RTC_MC146818_LIB
323	select SPARSE_IRQ
324	select SYSCTL_EXCEPTION_TRACE
325	select THREAD_INFO_IN_TASK
326	select TRACE_IRQFLAGS_SUPPORT
327	select TRACE_IRQFLAGS_NMI_SUPPORT
328	select USER_STACKTRACE_SUPPORT
329	select HAVE_ARCH_KCSAN			if X86_64
330	select PROC_PID_ARCH_STATUS		if PROC_FS
331	select HAS_SEPARATE_PREEMPT_RESCHED_BITS		if X86_64 && PREEMPT_COUNT
332	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
333	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
334	select FUNCTION_ALIGNMENT_4B
335	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
336	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
337	select ARCH_SUPPORTS_SCHED_SMT		if SMP
338	select SCHED_SMT			if SMP
339	select ARCH_SUPPORTS_SCHED_CLUSTER	if SMP
340	select ARCH_SUPPORTS_SCHED_MC		if SMP
341	select ARCH_SUPPORTS_SYSCALL_USER_DISPATCH
342	select HAVE_SINGLE_FTRACE_DIRECT_OPS	if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS
343
344config INSTRUCTION_DECODER
345	def_bool y
346	depends on KPROBES || PERF_EVENTS || UPROBES
347
348config OUTPUT_FORMAT
349	string
350	default "elf32-i386" if X86_32
351	default "elf64-x86-64" if X86_64
352
353config LOCKDEP_SUPPORT
354	def_bool y
355
356config STACKTRACE_SUPPORT
357	def_bool y
358
359config MMU
360	def_bool y
361
362config ARCH_MMAP_RND_BITS_MIN
363	default 28 if 64BIT
364	default 8
365
366config ARCH_MMAP_RND_BITS_MAX
367	default 32 if 64BIT
368	default 16
369
370config ARCH_MMAP_RND_COMPAT_BITS_MIN
371	default 8
372
373config ARCH_MMAP_RND_COMPAT_BITS_MAX
374	default 16
375
376config SBUS
377	bool
378
379config GENERIC_ISA_DMA
380	def_bool y
381	depends on ISA_DMA_API
382
383config GENERIC_CSUM
384	bool
385	default y if KMSAN || KASAN
386
387config GENERIC_BUG
388	def_bool y
389	depends on BUG
390	select GENERIC_BUG_RELATIVE_POINTERS
391
392config GENERIC_BUG_RELATIVE_POINTERS
393	bool
394
395config ARCH_MAY_HAVE_PC_FDC
396	def_bool y
397	depends on ISA_DMA_API
398
399config GENERIC_CALIBRATE_DELAY
400	def_bool y
401
402config ARCH_HAS_CPU_RELAX
403	def_bool y
404
405config ARCH_HIBERNATION_POSSIBLE
406	def_bool y
407
408config ARCH_SUSPEND_POSSIBLE
409	def_bool y
410
411config AUDIT_ARCH
412	def_bool y if X86_64
413
414config KASAN_SHADOW_OFFSET
415	hex
416	depends on KASAN
417	default 0xdffffc0000000000
418
419config HAVE_INTEL_TXT
420	def_bool y
421	depends on INTEL_IOMMU && ACPI
422
423config ARCH_SUPPORTS_UPROBES
424	def_bool y
425
426config FIX_EARLYCON_MEM
427	def_bool y
428
429config DYNAMIC_PHYSICAL_MASK
430	bool
431
432config PGTABLE_LEVELS
433	int
434	default 5 if X86_64
435	default 3 if X86_PAE
436	default 2
437
438menu "Processor type and features"
439
440config SMP
441	bool "Symmetric multi-processing support"
442	help
443	  This enables support for systems with more than one CPU. If you have
444	  a system with only one CPU, say N. If you have a system with more
445	  than one CPU, say Y.
446
447	  If you say N here, the kernel will run on uni- and multiprocessor
448	  machines, but will use only one CPU of a multiprocessor machine. If
449	  you say Y here, the kernel will run on many, but not all,
450	  uniprocessor machines. On a uniprocessor machine, the kernel
451	  will run faster if you say N here.
452
453	  People using multiprocessor machines who say Y here should also say
454	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
455	  Management" code will be disabled if you say Y here.
456
457	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
458	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
459	  <http://www.tldp.org/docs.html#howto>.
460
461	  If you don't know what to do here, say N.
462
463config X86_X2APIC
464	bool "x2APIC interrupt controller architecture support"
465	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
466	default y
467	help
468	  x2APIC is an interrupt controller architecture, a component of which
469	  (the local APIC) is present in the CPU. It allows faster access to
470	  the local APIC and supports a larger number of CPUs in the system
471	  than the predecessors.
472
473	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
474	  in 2019, but it can be disabled by the BIOS. It is also frequently
475	  emulated in virtual machines, even when the host CPU does not support
476	  it. Support in the CPU can be checked by executing
477		grep x2apic /proc/cpuinfo
478
479	  If this configuration option is disabled, the kernel will boot with
480	  very reduced functionality and performance on some platforms that
481	  have x2APIC enabled. On the other hand, on hardware that does not
482	  support x2APIC, a kernel with this option enabled will just fallback
483	  to older APIC implementations.
484
485	  If in doubt, say Y.
486
487config AMD_SECURE_AVIC
488	bool "AMD Secure AVIC"
489	depends on AMD_MEM_ENCRYPT && X86_X2APIC
490	help
491	  Enable this to get AMD Secure AVIC support on guests that have this feature.
492
493	  AMD Secure AVIC provides hardware acceleration for performance sensitive
494	  APIC accesses and support for managing guest owned APIC state for SEV-SNP
495	  guests. Secure AVIC does not support xAPIC mode. It has functional
496	  dependency on x2apic being enabled in the guest.
497
498	  If you don't know what to do here, say N.
499
500config X86_POSTED_MSI
501	bool "Enable MSI and MSI-x delivery by posted interrupts"
502	depends on X86_64 && IRQ_REMAP
503	help
504	  This enables MSIs that are under interrupt remapping to be delivered as
505	  posted interrupts to the host kernel. Interrupt throughput can
506	  potentially be improved by coalescing CPU notifications during high
507	  frequency bursts.
508
509	  If you don't know what to do here, say N.
510
511config X86_MPPARSE
512	bool "Enable MPS table" if ACPI
513	default y
514	depends on X86_LOCAL_APIC
515	help
516	  For old smp systems that do not have proper acpi support. Newer systems
517	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
518
519config X86_CPU_RESCTRL
520	bool "x86 CPU resource control support"
521	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
522	depends on MISC_FILESYSTEMS
523	select ARCH_HAS_CPU_RESCTRL
524	select RESCTRL_FS
525	select RESCTRL_FS_PSEUDO_LOCK
526	help
527	  Enable x86 CPU resource control support.
528
529	  Provide support for the allocation and monitoring of system resources
530	  usage by the CPU.
531
532	  Intel calls this Intel Resource Director Technology
533	  (Intel(R) RDT). More information about RDT can be found in the
534	  Intel x86 Architecture Software Developer Manual.
535
536	  AMD calls this AMD Platform Quality of Service (AMD QoS).
537	  More information about AMD QoS can be found in the AMD64 Technology
538	  Platform Quality of Service Extensions manual.
539
540	  Say N if unsure.
541
542config X86_CPU_RESCTRL_INTEL_AET
543	bool "Intel Application Energy Telemetry"
544	depends on X86_64 && X86_CPU_RESCTRL && CPU_SUP_INTEL && INTEL_PMT_TELEMETRY=y && INTEL_TPMI=y
545	help
546	  Enable per-RMID telemetry events in resctrl.
547
548	  Intel feature that collects per-RMID execution data
549	  about energy consumption, measure of frequency independent
550	  activity and other performance metrics. Data is aggregated
551	  per package.
552
553	  Say N if unsure.
554
555config X86_FRED
556	bool "Flexible Return and Event Delivery"
557	depends on X86_64
558	help
559	  When enabled, use Flexible Return and Event Delivery
560	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
561	  ring transitions and exception/interrupt handling if the
562	  system supports it.
563
564config X86_EXTENDED_PLATFORM
565	bool "Support for extended (non-PC) x86 platforms"
566	default y
567	help
568	  If you disable this option then the kernel will only support
569	  standard PC platforms. (which covers the vast majority of
570	  systems out there.)
571
572	  If you enable this option then you'll be able to select support
573	  for the following non-PC x86 platforms, depending on the value of
574	  CONFIG_64BIT.
575
576	  32-bit platforms (CONFIG_64BIT=n):
577		Goldfish (mostly Android emulator)
578		Intel CE media processor (CE4100) SoC
579		Intel Quark
580		RDC R-321x SoC
581
582	  64-bit platforms (CONFIG_64BIT=y):
583		Numascale NumaChip
584		ScaleMP vSMP
585		SGI Ultraviolet
586		Merrifield/Moorefield MID devices
587		Goldfish (mostly Android emulator)
588
589	  If you have one of these systems, or if you want to build a
590	  generic distribution kernel, say Y here - otherwise say N.
591
592# This is an alphabetically sorted list of 64 bit extended platforms
593# Please maintain the alphabetic order if and when there are additions
594config X86_NUMACHIP
595	bool "Numascale NumaChip"
596	depends on X86_64
597	depends on X86_EXTENDED_PLATFORM
598	depends on NUMA
599	depends on SMP
600	depends on X86_X2APIC
601	depends on PCI_MMCONFIG
602	help
603	  Adds support for Numascale NumaChip large-SMP systems. Needed to
604	  enable more than ~168 cores.
605	  If you don't have one of these, you should say N here.
606
607config X86_VSMP
608	bool "ScaleMP vSMP"
609	select HYPERVISOR_GUEST
610	select PARAVIRT
611	depends on X86_64 && PCI
612	depends on X86_EXTENDED_PLATFORM
613	depends on SMP
614	help
615	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
616	  supposed to run on these EM64T-based machines.  Only choose this option
617	  if you have one of these machines.
618
619config X86_UV
620	bool "SGI Ultraviolet"
621	depends on X86_64
622	depends on X86_EXTENDED_PLATFORM
623	depends on NUMA
624	depends on EFI
625	depends on KEXEC_CORE
626	depends on X86_X2APIC
627	depends on PCI
628	help
629	  This option is needed in order to support SGI Ultraviolet systems.
630	  If you don't have one of these, you should say N here.
631
632config X86_INTEL_MID
633	bool "Intel Z34xx/Z35xx MID platform support"
634	depends on X86_EXTENDED_PLATFORM
635	depends on X86_PLATFORM_DEVICES
636	depends on PCI
637	depends on X86_64 || (EXPERT && PCI_GOANY)
638	depends on X86_IO_APIC
639	select I2C
640	select DW_APB_TIMER
641	select INTEL_SCU_PCI
642	help
643	  Select to build a kernel capable of supporting 64-bit Intel MID
644	  (Mobile Internet Device) platform systems which do not have
645	  the PCI legacy interfaces.
646
647	  The only supported devices are the 22nm Merrified (Z34xx)
648	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
649	  a small number of Android devices such as the Asus Zenfone 2,
650	  Asus FonePad 8 and Dell Venue 7.
651
652	  If you are building for a PC class system or non-MID tablet
653	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
654
655	  Intel MID platforms are based on an Intel processor and chipset which
656	  consume less power than most of the x86 derivatives.
657
658config X86_GOLDFISH
659	bool "Goldfish (Virtual Platform)"
660	depends on X86_EXTENDED_PLATFORM
661	help
662	  Enable support for the Goldfish virtual platform used primarily
663	  for Android development. Unless you are building for the Android
664	  Goldfish emulator say N here.
665
666# Following is an alphabetically sorted list of 32 bit extended platforms
667# Please maintain the alphabetic order if and when there are additions
668
669config X86_INTEL_CE
670	bool "CE4100 TV platform"
671	depends on PCI
672	depends on PCI_GODIRECT
673	depends on X86_IO_APIC
674	depends on X86_32
675	depends on X86_EXTENDED_PLATFORM
676	select X86_REBOOTFIXUPS
677	select OF
678	select OF_EARLY_FLATTREE
679	help
680	  Select for the Intel CE media processor (CE4100) SOC.
681	  This option compiles in support for the CE4100 SOC for settop
682	  boxes and media devices.
683
684config X86_INTEL_QUARK
685	bool "Intel Quark platform support"
686	depends on X86_32
687	depends on X86_EXTENDED_PLATFORM
688	depends on X86_PLATFORM_DEVICES
689	depends on PCI
690	depends on PCI_GOANY
691	depends on X86_IO_APIC
692	select IOSF_MBI
693	select INTEL_IMR
694	select COMMON_CLK
695	help
696	  Select to include support for Quark X1000 SoC.
697	  Say Y here if you have a Quark based system such as the Arduino
698	  compatible Intel Galileo.
699
700config X86_INTEL_LPSS
701	bool "Intel Low Power Subsystem Support"
702	depends on X86 && ACPI && PCI
703	select COMMON_CLK
704	select PINCTRL
705	select IOSF_MBI
706	help
707	  Select to build support for Intel Low Power Subsystem such as
708	  found on Intel Lynxpoint PCH. Selecting this option enables
709	  things like clock tree (common clock framework) and pincontrol
710	  which are needed by the LPSS peripheral drivers.
711
712config X86_AMD_PLATFORM_DEVICE
713	bool "AMD ACPI2Platform devices support"
714	depends on ACPI
715	select COMMON_CLK
716	select PINCTRL
717	help
718	  Select to interpret AMD specific ACPI device to platform device
719	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
720	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
721	  implemented under PINCTRL subsystem.
722
723config IOSF_MBI
724	tristate "Intel SoC IOSF Sideband support for SoC platforms"
725	depends on PCI
726	help
727	  This option enables sideband register access support for Intel SoC
728	  platforms. On these platforms the IOSF sideband is used in lieu of
729	  MSR's for some register accesses, mostly but not limited to thermal
730	  and power. Drivers may query the availability of this device to
731	  determine if they need the sideband in order to work on these
732	  platforms. The sideband is available on the following SoC products.
733	  This list is not meant to be exclusive.
734	   - BayTrail
735	   - Braswell
736	   - Quark
737
738	  You should say Y if you are running a kernel on one of these SoC's.
739
740config IOSF_MBI_DEBUG
741	bool "Enable IOSF sideband access through debugfs"
742	depends on IOSF_MBI && DEBUG_FS
743	help
744	  Select this option to expose the IOSF sideband access registers (MCR,
745	  MDR, MCRX) through debugfs to write and read register information from
746	  different units on the SoC. This is most useful for obtaining device
747	  state information for debug and analysis. As this is a general access
748	  mechanism, users of this option would have specific knowledge of the
749	  device they want to access.
750
751	  If you don't require the option or are in doubt, say N.
752
753config X86_SUPPORTS_MEMORY_FAILURE
754	def_bool y
755	# MCE code calls memory_failure():
756	depends on X86_MCE
757	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
758	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
759	depends on X86_64 || !SPARSEMEM
760	select ARCH_SUPPORTS_MEMORY_FAILURE
761
762config X86_32_IRIS
763	tristate "Eurobraille/Iris poweroff module"
764	depends on X86_32
765	help
766	  The Iris machines from EuroBraille do not have APM or ACPI support
767	  to shut themselves down properly.  A special I/O sequence is
768	  needed to do so, which is what this module does at
769	  kernel shutdown.
770
771	  This is only for Iris machines from EuroBraille.
772
773	  If unused, say N.
774
775config SCHED_OMIT_FRAME_POINTER
776	def_bool y
777	prompt "Single-depth WCHAN output"
778	depends on X86
779	help
780	  Calculate simpler /proc/<PID>/wchan values. If this option
781	  is disabled then wchan values will recurse back to the
782	  caller function. This provides more accurate wchan values,
783	  at the expense of slightly more scheduling overhead.
784
785	  If in doubt, say "Y".
786
787menuconfig HYPERVISOR_GUEST
788	bool "Linux guest support"
789	help
790	  Say Y here to enable options for running Linux under various hyper-
791	  visors. This option enables basic hypervisor detection and platform
792	  setup.
793
794	  If you say N, all options in this submenu will be skipped and
795	  disabled, and Linux guest support won't be built in.
796
797if HYPERVISOR_GUEST
798
799config PARAVIRT
800	bool "Enable paravirtualization code"
801	depends on HAVE_STATIC_CALL
802	select HAVE_PV_STEAL_CLOCK_GEN
803	help
804	  This changes the kernel so it can modify itself when it is run
805	  under a hypervisor, potentially improving performance significantly
806	  over full virtualization.  However, when run without a hypervisor
807	  the kernel is theoretically slower and slightly larger.
808
809config PARAVIRT_XXL
810	bool
811	depends on X86_64
812	select ARCH_HAS_LAZY_MMU_MODE
813
814config PARAVIRT_SPINLOCKS
815	bool "Paravirtualization layer for spinlocks"
816	depends on PARAVIRT && SMP
817	help
818	  Paravirtualized spinlocks allow a pvops backend to replace the
819	  spinlock implementation with something virtualization-friendly
820	  (for example, block the virtual CPU rather than spinning).
821
822	  It has a minimal impact on native kernels and gives a nice performance
823	  benefit on paravirtualized KVM / Xen kernels.
824
825	  If you are unsure how to answer this question, answer Y.
826
827config X86_HV_CALLBACK_VECTOR
828	def_bool n
829
830source "arch/x86/xen/Kconfig"
831
832config KVM_GUEST
833	bool "KVM Guest support (including kvmclock)"
834	depends on PARAVIRT
835	select PARAVIRT_CLOCK
836	select ARCH_CPUIDLE_HALTPOLL
837	select X86_HV_CALLBACK_VECTOR
838	default y
839	help
840	  This option enables various optimizations for running under the KVM
841	  hypervisor. It includes a paravirtualized clock, so that instead
842	  of relying on a PIT (or probably other) emulation by the
843	  underlying device model, the host provides the guest with
844	  timing infrastructure such as time of day, and system time
845
846config ARCH_CPUIDLE_HALTPOLL
847	def_bool n
848	prompt "Disable host haltpoll when loading haltpoll driver"
849	help
850	  If virtualized under KVM, disable host haltpoll.
851
852config PVH
853	bool "Support for running PVH guests"
854	help
855	  This option enables the PVH entry point for guest virtual machines
856	  as specified in the x86/HVM direct boot ABI.
857
858config PARAVIRT_TIME_ACCOUNTING
859	bool "Paravirtual steal time accounting"
860	depends on PARAVIRT
861	help
862	  Select this option to enable fine granularity task steal time
863	  accounting. Time spent executing other tasks in parallel with
864	  the current vCPU is discounted from the vCPU power. To account for
865	  that, there can be a small performance impact.
866
867	  If in doubt, say N here.
868
869config PARAVIRT_CLOCK
870	bool
871
872config JAILHOUSE_GUEST
873	bool "Jailhouse non-root cell support"
874	depends on X86_64 && PCI
875	select X86_PM_TIMER
876	help
877	  This option allows to run Linux as guest in a Jailhouse non-root
878	  cell. You can leave this option disabled if you only want to start
879	  Jailhouse and run Linux afterwards in the root cell.
880
881config ACRN_GUEST
882	bool "ACRN Guest support"
883	depends on X86_64
884	select X86_HV_CALLBACK_VECTOR
885	help
886	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
887	  a flexible, lightweight reference open-source hypervisor, built with
888	  real-time and safety-criticality in mind. It is built for embedded
889	  IOT with small footprint and real-time features. More details can be
890	  found in https://projectacrn.org/.
891
892config BHYVE_GUEST
893	bool "Bhyve (BSD Hypervisor) Guest support"
894	depends on X86_64
895	help
896	  This option allows to run Linux to recognise when it is running as a
897	  guest in the Bhyve hypervisor, and to support more than 255 vCPUs when
898	  when doing so. More details about Bhyve can be found at https://bhyve.org
899	  and https://wiki.freebsd.org/bhyve/.
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	depends on PARAVIRT
907	select ARCH_HAS_CC_PLATFORM
908	select X86_MEM_ENCRYPT
909	select X86_MCE
910	select UNACCEPTED_MEMORY
911	help
912	  Support running as a guest under Intel TDX.  Without this support,
913	  the guest kernel can not boot or run under TDX.
914	  TDX includes memory encryption and integrity capabilities
915	  which protect the confidentiality and integrity of guest
916	  memory contents and CPU state. TDX guests are protected from
917	  some attacks from the VMM.
918
919endif # HYPERVISOR_GUEST
920
921source "arch/x86/Kconfig.cpu"
922
923config HPET_TIMER
924	def_bool X86_64
925	prompt "HPET Timer Support" if X86_32
926	help
927	  Use the IA-PC HPET (High Precision Event Timer) to manage
928	  time in preference to the PIT and RTC, if a HPET is
929	  present.
930	  HPET is the next generation timer replacing legacy 8254s.
931	  The HPET provides a stable time base on SMP
932	  systems, unlike the TSC, but it is more expensive to access,
933	  as it is off-chip.  The interface used is documented
934	  in the HPET spec, revision 1.
935
936	  You can safely choose Y here.  However, HPET will only be
937	  activated if the platform and the BIOS support this feature.
938	  Otherwise the 8254 will be used for timing services.
939
940	  Choose N to continue using the legacy 8254 timer.
941
942config HPET_EMULATE_RTC
943	def_bool y
944	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
945
946# Mark as expert because too many people got it wrong.
947# The code disables itself when not needed.
948config DMI
949	default y
950	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
951	bool "Enable DMI scanning" if EXPERT
952	help
953	  Enabled scanning of DMI to identify machine quirks. Say Y
954	  here unless you have verified that your setup is not
955	  affected by entries in the DMI blacklist. Required by PNP
956	  BIOS code.
957
958config GART_IOMMU
959	bool "Old AMD GART IOMMU support"
960	select IOMMU_HELPER
961	select SWIOTLB
962	depends on X86_64 && PCI && AMD_NB
963	help
964	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
965	  GART based hardware IOMMUs.
966
967	  The GART supports full DMA access for devices with 32-bit access
968	  limitations, on systems with more than 3 GB. This is usually needed
969	  for USB, sound, many IDE/SATA chipsets and some other devices.
970
971	  Newer systems typically have a modern AMD IOMMU, supported via
972	  the CONFIG_AMD_IOMMU=y config option.
973
974	  In normal configurations this driver is only active when needed:
975	  there's more than 3 GB of memory and the system contains a
976	  32-bit limited device.
977
978	  If unsure, say Y.
979
980config BOOT_VESA_SUPPORT
981	bool
982	help
983	  If true, at least one selected framebuffer driver can take advantage
984	  of VESA video modes set at an early boot stage via the vga= parameter.
985
986config MAXSMP
987	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
988	depends on X86_64 && SMP && DEBUG_KERNEL
989	select CPUMASK_OFFSTACK
990	help
991	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
992	  If unsure, say N.
993
994#
995# The maximum number of CPUs supported:
996#
997# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
998# and which can be configured interactively in the
999# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
1000#
1001# The ranges are different on 32-bit and 64-bit kernels, depending on
1002# hardware capabilities and scalability features of the kernel.
1003#
1004# ( If MAXSMP is enabled we just use the highest possible value and disable
1005#   interactive configuration. )
1006#
1007
1008config NR_CPUS_RANGE_BEGIN
1009	int
1010	default NR_CPUS_RANGE_END if MAXSMP
1011	default    1 if !SMP
1012	default    2
1013
1014config NR_CPUS_RANGE_END
1015	int
1016	depends on X86_32
1017	default    8 if  SMP
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    8 if  SMP
1031	default    1 if !SMP
1032
1033config NR_CPUS_DEFAULT
1034	int
1035	depends on X86_64
1036	default 8192 if  MAXSMP
1037	default   64 if  SMP
1038	default    1 if !SMP
1039
1040config NR_CPUS
1041	int "Maximum number of CPUs" if SMP && !MAXSMP
1042	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1043	default NR_CPUS_DEFAULT
1044	help
1045	  This allows you to specify the maximum number of CPUs which this
1046	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1047	  supported value is 8192, otherwise the maximum value is 512.  The
1048	  minimum value which makes sense is 2.
1049
1050	  This is purely to save memory: each supported CPU adds about 8KB
1051	  to the kernel image.
1052
1053config SCHED_MC_PRIO
1054	bool "CPU core priorities scheduler support"
1055	depends on SCHED_MC
1056	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1057	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1058	select CPU_FREQ
1059	default y
1060	help
1061	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1062	  core ordering determined at manufacturing time, which allows
1063	  certain cores to reach higher turbo frequencies (when running
1064	  single threaded workloads) than others.
1065
1066	  Enabling this kernel feature teaches the scheduler about
1067	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1068	  scheduler's CPU selection logic accordingly, so that higher
1069	  overall system performance can be achieved.
1070
1071	  This feature will have no effect on CPUs without this feature.
1072
1073	  If unsure say Y here.
1074
1075config UP_LATE_INIT
1076	def_bool y
1077	depends on !SMP && X86_LOCAL_APIC
1078
1079config X86_UP_APIC
1080	bool "Local APIC support on uniprocessors" if !PCI_MSI
1081	default PCI_MSI
1082	depends on X86_32 && !SMP
1083	help
1084	  A local APIC (Advanced Programmable Interrupt Controller) is an
1085	  integrated interrupt controller in the CPU. If you have a single-CPU
1086	  system which has a processor with a local APIC, you can say Y here to
1087	  enable and use it. If you say Y here even though your machine doesn't
1088	  have a local APIC, then the kernel will still run with no slowdown at
1089	  all. The local APIC supports CPU-generated self-interrupts (timer,
1090	  performance counters), and the NMI watchdog which detects hard
1091	  lockups.
1092
1093config X86_UP_IOAPIC
1094	bool "IO-APIC support on uniprocessors"
1095	depends on X86_UP_APIC
1096	help
1097	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1098	  SMP-capable replacement for PC-style interrupt controllers. Most
1099	  SMP systems and many recent uniprocessor systems have one.
1100
1101	  If you have a single-CPU system with an IO-APIC, you can say Y here
1102	  to use it. If you say Y here even though your machine doesn't have
1103	  an IO-APIC, then the kernel will still run with no slowdown at all.
1104
1105config X86_LOCAL_APIC
1106	def_bool y
1107	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1108	select IRQ_DOMAIN_HIERARCHY
1109
1110config ACPI_MADT_WAKEUP
1111	def_bool y
1112	depends on X86_64
1113	depends on ACPI
1114	depends on SMP
1115	depends on X86_LOCAL_APIC
1116
1117config X86_IO_APIC
1118	def_bool y
1119	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1120
1121config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1122	bool "Reroute for broken boot IRQs"
1123	depends on X86_IO_APIC
1124	help
1125	  This option enables a workaround that fixes a source of
1126	  spurious interrupts. This is recommended when threaded
1127	  interrupt handling is used on systems where the generation of
1128	  superfluous "boot interrupts" cannot be disabled.
1129
1130	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1131	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1132	  kernel does during interrupt handling). On chipsets where this
1133	  boot IRQ generation cannot be disabled, this workaround keeps
1134	  the original IRQ line masked so that only the equivalent "boot
1135	  IRQ" is delivered to the CPUs. The workaround also tells the
1136	  kernel to set up the IRQ handler on the boot IRQ line. In this
1137	  way only one interrupt is delivered to the kernel. Otherwise
1138	  the spurious second interrupt may cause the kernel to bring
1139	  down (vital) interrupt lines.
1140
1141	  Only affects "broken" chipsets. Interrupt sharing may be
1142	  increased on these systems.
1143
1144config X86_MCE
1145	bool "Machine Check / overheating reporting"
1146	select GENERIC_ALLOCATOR
1147	default y
1148	help
1149	  Machine Check support allows the processor to notify the
1150	  kernel if it detects a problem (e.g. overheating, data corruption).
1151	  The action the kernel takes depends on the severity of the problem,
1152	  ranging from warning messages to halting the machine.
1153
1154config X86_MCELOG_LEGACY
1155	bool "Support for deprecated /dev/mcelog character device"
1156	depends on X86_MCE
1157	help
1158	  Enable support for /dev/mcelog which is needed by the old mcelog
1159	  userspace logging daemon. Consider switching to the new generation
1160	  rasdaemon solution.
1161
1162config X86_MCE_INTEL
1163	def_bool y
1164	prompt "Intel MCE features"
1165	depends on X86_MCE && X86_LOCAL_APIC
1166	help
1167	  Additional support for intel specific MCE features such as
1168	  the thermal monitor.
1169
1170config X86_MCE_AMD
1171	def_bool y
1172	prompt "AMD MCE features"
1173	depends on X86_MCE && X86_LOCAL_APIC
1174	help
1175	  Additional support for AMD specific MCE features such as
1176	  the DRAM Error Threshold.
1177
1178config X86_ANCIENT_MCE
1179	bool "Support for old Pentium 5 / WinChip machine checks"
1180	depends on X86_32 && X86_MCE
1181	help
1182	  Include support for machine check handling on old Pentium 5 or WinChip
1183	  systems. These typically need to be enabled explicitly on the command
1184	  line.
1185
1186config X86_MCE_THRESHOLD
1187	depends on X86_MCE_AMD || X86_MCE_INTEL
1188	def_bool y
1189
1190config X86_MCE_INJECT
1191	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1192	tristate "Machine check injector support"
1193	help
1194	  Provide support for injecting machine checks for testing purposes.
1195	  If you don't know what a machine check is and you don't do kernel
1196	  QA it is safe to say n.
1197
1198source "arch/x86/events/Kconfig"
1199
1200config X86_LEGACY_VM86
1201	bool "Legacy VM86 support"
1202	depends on X86_32
1203	help
1204	  This option allows user programs to put the CPU into V8086
1205	  mode, which is an 80286-era approximation of 16-bit real mode.
1206
1207	  Some very old versions of X and/or vbetool require this option
1208	  for user mode setting.  Similarly, DOSEMU will use it if
1209	  available to accelerate real mode DOS programs.  However, any
1210	  recent version of DOSEMU, X, or vbetool should be fully
1211	  functional even without kernel VM86 support, as they will all
1212	  fall back to software emulation. Nevertheless, if you are using
1213	  a 16-bit DOS program where 16-bit performance matters, vm86
1214	  mode might be faster than emulation and you might want to
1215	  enable this option.
1216
1217	  Note that any app that works on a 64-bit kernel is unlikely to
1218	  need this option, as 64-bit kernels don't, and can't, support
1219	  V8086 mode. This option is also unrelated to 16-bit protected
1220	  mode and is not needed to run most 16-bit programs under Wine.
1221
1222	  Enabling this option increases the complexity of the kernel
1223	  and slows down exception handling a tiny bit.
1224
1225	  If unsure, say N here.
1226
1227config VM86
1228	bool
1229	default X86_LEGACY_VM86
1230
1231config X86_16BIT
1232	bool "Enable support for 16-bit segments" if EXPERT
1233	default y
1234	depends on MODIFY_LDT_SYSCALL
1235	help
1236	  This option is required by programs like Wine to run 16-bit
1237	  protected mode legacy code on x86 processors.  Disabling
1238	  this option saves about 300 bytes on i386, or around 6K text
1239	  plus 16K runtime memory on x86-64,
1240
1241config X86_ESPFIX32
1242	def_bool y
1243	depends on X86_16BIT && X86_32
1244
1245config X86_ESPFIX64
1246	def_bool y
1247	depends on X86_16BIT && X86_64
1248
1249config X86_VSYSCALL_EMULATION
1250	bool "Enable vsyscall emulation" if EXPERT
1251	default y
1252	depends on X86_64
1253	help
1254	  This enables emulation of the legacy vsyscall page.  Disabling
1255	  it is roughly equivalent to booting with vsyscall=none, except
1256	  that it will also disable the helpful warning if a program
1257	  tries to use a vsyscall.  With this option set to N, offending
1258	  programs will just segfault, citing addresses of the form
1259	  0xffffffffff600?00.
1260
1261	  This option is required by many programs built before 2013, and
1262	  care should be used even with newer programs if set to N.
1263
1264	  Disabling this option saves about 7K of kernel size and
1265	  possibly 4K of additional runtime pagetable memory.
1266
1267config X86_IOPL_IOPERM
1268	bool "IOPERM and IOPL Emulation"
1269	default y
1270	help
1271	  This enables the ioperm() and iopl() syscalls which are necessary
1272	  for legacy applications.
1273
1274	  Legacy IOPL support is an overbroad mechanism which allows user
1275	  space aside of accessing all 65536 I/O ports also to disable
1276	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1277	  capabilities and permission from potentially active security
1278	  modules.
1279
1280	  The emulation restricts the functionality of the syscall to
1281	  only allowing the full range I/O port access, but prevents the
1282	  ability to disable interrupts from user space which would be
1283	  granted if the hardware IOPL mechanism would be used.
1284
1285config TOSHIBA
1286	tristate "Toshiba Laptop support"
1287	depends on X86_32
1288	help
1289	  This adds a driver to safely access the System Management Mode of
1290	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1291	  not work on models with a Phoenix BIOS. The System Management Mode
1292	  is used to set the BIOS and power saving options on Toshiba portables.
1293
1294	  For information on utilities to make use of this driver see the
1295	  Toshiba Linux utilities web site at:
1296	  <http://www.buzzard.org.uk/toshiba/>.
1297
1298	  Say Y if you intend to run this kernel on a Toshiba portable.
1299	  Say N otherwise.
1300
1301config X86_REBOOTFIXUPS
1302	bool "Enable X86 board specific fixups for reboot"
1303	depends on X86_32
1304	help
1305	  This enables chipset and/or board specific fixups to be done
1306	  in order to get reboot to work correctly. This is only needed on
1307	  some combinations of hardware and BIOS. The symptom, for which
1308	  this config is intended, is when reboot ends with a stalled/hung
1309	  system.
1310
1311	  Currently, the only fixup is for the Geode machines using
1312	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1313
1314	  Say Y if you want to enable the fixup. Currently, it's safe to
1315	  enable this option even if you don't need it.
1316	  Say N otherwise.
1317
1318config MICROCODE
1319	def_bool y
1320	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1321	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1322
1323config MICROCODE_INITRD32
1324	def_bool y
1325	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1326
1327config MICROCODE_LATE_LOADING
1328	bool "Late microcode loading (DANGEROUS)"
1329	default n
1330	depends on MICROCODE && SMP
1331	help
1332	  Loading microcode late, when the system is up and executing instructions
1333	  is a tricky business and should be avoided if possible. Just the sequence
1334	  of synchronizing all cores and SMT threads is one fragile dance which does
1335	  not guarantee that cores might not softlock after the loading. Therefore,
1336	  use this at your own risk. Late loading taints the kernel unless the
1337	  microcode header indicates that it is safe for late loading via the
1338	  minimal revision check. This minimal revision check can be enforced on
1339	  the kernel command line with "microcode=force_minrev".
1340
1341config MICROCODE_LATE_FORCE_MINREV
1342	bool "Enforce late microcode loading minimal revision check"
1343	default n
1344	depends on MICROCODE_LATE_LOADING
1345	help
1346	  To prevent that users load microcode late which modifies already
1347	  in use features, newer microcode patches have a minimum revision field
1348	  in the microcode header, which tells the kernel which minimum
1349	  revision must be active in the CPU to safely load that new microcode
1350	  late into the running system. If disabled the check will not
1351	  be enforced but the kernel will be tainted when the minimal
1352	  revision check fails.
1353
1354	  This minimal revision check can also be controlled via the
1355	  "microcode=force_minrev" parameter on the kernel command line.
1356
1357	  If unsure say Y.
1358
1359config MICROCODE_DBG
1360	bool "Enable microcode loader debugging"
1361	default n
1362	depends on MICROCODE
1363	help
1364	  Enable code which allows to debug the microcode loader. When running
1365	  in a guest the patch loading is simulated but everything else
1366	  related to patch parsing and handling is done as on baremetal with
1367	  the purpose of debugging solely the software side of things. On
1368	  baremetal, it simply dumps additional debugging information during
1369	  normal operation.
1370
1371	  You almost certainly want to say n here.
1372
1373config X86_MSR
1374	tristate "/dev/cpu/*/msr - Model-specific register support"
1375	help
1376	  This device gives privileged processes access to the x86
1377	  Model-Specific Registers (MSRs).  It is a character device with
1378	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1379	  MSR accesses are directed to a specific CPU on multi-processor
1380	  systems.
1381
1382config X86_CPUID
1383	tristate "/dev/cpu/*/cpuid - CPU information support"
1384	help
1385	  This device gives processes access to the x86 CPUID instruction to
1386	  be executed on a specific processor.  It is a character device
1387	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1388	  /dev/cpu/31/cpuid.
1389
1390config HIGHMEM4G
1391	bool "High Memory Support"
1392	depends on X86_32
1393	help
1394	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1395	  However, the address space of 32-bit x86 processors is only 4
1396	  Gigabytes large. That means that, if you have a large amount of
1397	  physical memory, not all of it can be "permanently mapped" by the
1398	  kernel. The physical memory that's not permanently mapped is called
1399	  "high memory".
1400
1401	  If you are compiling a kernel which will never run on a machine with
1402	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1403	  choice and suitable for most users). This will result in a "3GB/1GB"
1404	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1405	  space and the remaining part of the 4GB virtual memory space is used
1406	  by the kernel to permanently map as much physical memory as
1407	  possible.
1408
1409	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1410	  answer "Y" here.
1411
1412	  If unsure, say N.
1413
1414choice
1415	prompt "Memory split" if EXPERT
1416	default VMSPLIT_3G
1417	depends on X86_32
1418	help
1419	  Select the desired split between kernel and user memory.
1420
1421	  If the address range available to the kernel is less than the
1422	  physical memory installed, the remaining memory will be available
1423	  as "high memory". Accessing high memory is a little more costly
1424	  than low memory, as it needs to be mapped into the kernel first.
1425	  Note that increasing the kernel address space limits the range
1426	  available to user programs, making the address space there
1427	  tighter.  Selecting anything other than the default 3G/1G split
1428	  will also likely make your kernel incompatible with binary-only
1429	  kernel modules.
1430
1431	  If you are not absolutely sure what you are doing, leave this
1432	  option alone!
1433
1434	config VMSPLIT_3G
1435		bool "3G/1G user/kernel split"
1436	config VMSPLIT_3G_OPT
1437		depends on !X86_PAE
1438		bool "3G/1G user/kernel split (for full 1G low memory)"
1439	config VMSPLIT_2G
1440		bool "2G/2G user/kernel split"
1441	config VMSPLIT_2G_OPT
1442		depends on !X86_PAE
1443		bool "2G/2G user/kernel split (for full 2G low memory)"
1444	config VMSPLIT_1G
1445		bool "1G/3G user/kernel split"
1446endchoice
1447
1448config PAGE_OFFSET
1449	hex
1450	default 0xB0000000 if VMSPLIT_3G_OPT
1451	default 0x80000000 if VMSPLIT_2G
1452	default 0x78000000 if VMSPLIT_2G_OPT
1453	default 0x40000000 if VMSPLIT_1G
1454	default 0xC0000000
1455	depends on X86_32
1456
1457config HIGHMEM
1458	def_bool HIGHMEM4G
1459
1460config X86_PAE
1461	bool "PAE (Physical Address Extension) Support"
1462	depends on X86_32 && X86_HAVE_PAE
1463	select PHYS_ADDR_T_64BIT
1464	help
1465	  PAE is required for NX support, and furthermore enables
1466	  larger swapspace support for non-overcommit purposes. It
1467	  has the cost of more pagetable lookup overhead, and also
1468	  consumes more pagetable space per process.
1469
1470config X86_DIRECT_GBPAGES
1471	def_bool y
1472	depends on X86_64
1473	help
1474	  Certain kernel features effectively disable kernel
1475	  linear 1 GB mappings (even if the CPU otherwise
1476	  supports them), so don't confuse the user by printing
1477	  that we have them enabled.
1478
1479config X86_CPA_STATISTICS
1480	bool "Enable statistic for Change Page Attribute"
1481	depends on DEBUG_FS
1482	help
1483	  Expose statistics about the Change Page Attribute mechanism, which
1484	  helps to determine the effectiveness of preserving large and huge
1485	  page mappings when mapping protections are changed.
1486
1487config X86_MEM_ENCRYPT
1488	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1489	select DYNAMIC_PHYSICAL_MASK
1490	def_bool n
1491
1492config AMD_MEM_ENCRYPT
1493	bool "AMD Secure Memory Encryption (SME) support"
1494	depends on X86_64 && CPU_SUP_AMD
1495	depends on EFI_STUB
1496	select DMA_COHERENT_POOL
1497	select ARCH_USE_MEMREMAP_PROT
1498	select INSTRUCTION_DECODER
1499	select ARCH_HAS_CC_PLATFORM
1500	select X86_MEM_ENCRYPT
1501	select UNACCEPTED_MEMORY
1502	select CRYPTO_LIB_AES_GCM
1503	help
1504	  Say yes to enable support for the encryption of system memory.
1505	  This requires an AMD processor that supports Secure Memory
1506	  Encryption (SME).
1507
1508# Common NUMA Features
1509config NUMA
1510	bool "NUMA Memory Allocation and Scheduler Support"
1511	depends on SMP
1512	depends on X86_64
1513	select USE_PERCPU_NUMA_NODE_ID
1514	select OF_NUMA if OF
1515	help
1516	  Enable NUMA (Non-Uniform Memory Access) support.
1517
1518	  The kernel will try to allocate memory used by a CPU on the
1519	  local memory controller of the CPU and add some more
1520	  NUMA awareness to the kernel.
1521
1522	  For 64-bit this is recommended if the system is Intel Core i7
1523	  (or later), AMD Opteron, or EM64T NUMA.
1524
1525	  Otherwise, you should say N.
1526
1527config AMD_NUMA
1528	def_bool y
1529	prompt "Old style AMD Opteron NUMA detection"
1530	depends on X86_64 && NUMA && PCI
1531	help
1532	  Enable AMD NUMA node topology detection.  You should say Y here if
1533	  you have a multi processor AMD system. This uses an old method to
1534	  read the NUMA configuration directly from the builtin Northbridge
1535	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1536	  which also takes priority if both are compiled in.
1537
1538config X86_64_ACPI_NUMA
1539	def_bool y
1540	prompt "ACPI NUMA detection"
1541	depends on X86_64 && NUMA && ACPI && PCI
1542	select ACPI_NUMA
1543	help
1544	  Enable ACPI SRAT based node topology detection.
1545
1546config NODES_SHIFT
1547	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1548	range 1 10
1549	default "10" if MAXSMP
1550	default "6" if X86_64
1551	default "3"
1552	depends on NUMA
1553	help
1554	  Specify the maximum number of NUMA Nodes available on the target
1555	  system.  Increases memory reserved to accommodate various tables.
1556
1557config ARCH_FLATMEM_ENABLE
1558	def_bool y
1559	depends on X86_32 && !NUMA
1560
1561config ARCH_SPARSEMEM_ENABLE
1562	def_bool y
1563	select SPARSEMEM_STATIC if X86_32
1564	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1565
1566config ARCH_SPARSEMEM_DEFAULT
1567	def_bool X86_64 || (NUMA && X86_32)
1568
1569config ARCH_SELECT_MEMORY_MODEL
1570	def_bool y
1571	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1572
1573config ARCH_MEMORY_PROBE
1574	bool "Enable sysfs memory/probe interface"
1575	depends on MEMORY_HOTPLUG
1576	help
1577	  This option enables a sysfs memory/probe interface for testing.
1578	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1579	  If you are unsure how to answer this question, answer N.
1580
1581config ARCH_PROC_KCORE_TEXT
1582	def_bool y
1583	depends on X86_64 && PROC_KCORE
1584
1585config ILLEGAL_POINTER_VALUE
1586	hex
1587	default 0 if X86_32
1588	default 0xdead000000000000 if X86_64
1589
1590config X86_PMEM_LEGACY_DEVICE
1591	bool
1592
1593config X86_PMEM_LEGACY
1594	tristate "Support non-standard NVDIMMs and ADR protected memory"
1595	depends on PHYS_ADDR_T_64BIT
1596	depends on BLK_DEV
1597	select X86_PMEM_LEGACY_DEVICE
1598	select NUMA_KEEP_MEMINFO if NUMA
1599	select LIBNVDIMM
1600	help
1601	  Treat memory marked using the non-standard e820 type of 12 as used
1602	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1603	  The kernel will offer these regions to the 'pmem' driver so
1604	  they can be used for persistent storage.
1605
1606	  Say Y if unsure.
1607
1608config X86_CHECK_BIOS_CORRUPTION
1609	bool "Check for low memory corruption"
1610	help
1611	  Periodically check for memory corruption in low memory, which
1612	  is suspected to be caused by BIOS.  Even when enabled in the
1613	  configuration, it is disabled at runtime.  Enable it by
1614	  setting "memory_corruption_check=1" on the kernel command
1615	  line.  By default it scans the low 64k of memory every 60
1616	  seconds; see the memory_corruption_check_size and
1617	  memory_corruption_check_period parameters in
1618	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1619
1620	  When enabled with the default parameters, this option has
1621	  almost no overhead, as it reserves a relatively small amount
1622	  of memory and scans it infrequently.  It both detects corruption
1623	  and prevents it from affecting the running system.
1624
1625	  It is, however, intended as a diagnostic tool; if repeatable
1626	  BIOS-originated corruption always affects the same memory,
1627	  you can use memmap= to prevent the kernel from using that
1628	  memory.
1629
1630config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1631	bool "Set the default setting of memory_corruption_check"
1632	depends on X86_CHECK_BIOS_CORRUPTION
1633	default y
1634	help
1635	  Set whether the default state of memory_corruption_check is
1636	  on or off.
1637
1638config MTRR
1639	def_bool y
1640	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1641	help
1642	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1643	  the Memory Type Range Registers (MTRRs) may be used to control
1644	  processor access to memory ranges. This is most useful if you have
1645	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1646	  allows bus write transfers to be combined into a larger transfer
1647	  before bursting over the PCI/AGP bus. This can increase performance
1648	  of image write operations 2.5 times or more. Saying Y here creates a
1649	  /proc/mtrr file which may be used to manipulate your processor's
1650	  MTRRs. Typically the X server should use this.
1651
1652	  This code has a reasonably generic interface so that similar
1653	  control registers on other processors can be easily supported
1654	  as well:
1655
1656	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1657	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1658	  these, the ARRs are used to emulate the MTRRs.
1659	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1660	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1661	  write-combining. All of these processors are supported by this code
1662	  and it makes sense to say Y here if you have one of them.
1663
1664	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1665	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1666	  can lead to all sorts of problems, so it's good to say Y here.
1667
1668	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1669	  just add about 9 KB to your kernel.
1670
1671	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1672
1673config MTRR_SANITIZER
1674	def_bool y
1675	prompt "MTRR cleanup support"
1676	depends on MTRR
1677	help
1678	  Convert MTRR layout from continuous to discrete, so X drivers can
1679	  add writeback entries.
1680
1681	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1682	  The largest mtrr entry size for a continuous block can be set with
1683	  mtrr_chunk_size.
1684
1685	  If unsure, say Y.
1686
1687config MTRR_SANITIZER_ENABLE_DEFAULT
1688	int "MTRR cleanup enable value (0-1)"
1689	range 0 1
1690	default "0"
1691	depends on MTRR_SANITIZER
1692	help
1693	  Enable mtrr cleanup default value
1694
1695config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1696	int "MTRR cleanup spare reg num (0-7)"
1697	range 0 7
1698	default "1"
1699	depends on MTRR_SANITIZER
1700	help
1701	  mtrr cleanup spare entries default, it can be changed via
1702	  mtrr_spare_reg_nr=N on the kernel command line.
1703
1704config X86_PAT
1705	def_bool y
1706	prompt "x86 PAT support" if EXPERT
1707	depends on MTRR
1708	select ARCH_USES_PG_ARCH_2
1709	help
1710	  Use PAT attributes to setup page level cache control.
1711
1712	  PATs are the modern equivalents of MTRRs and are much more
1713	  flexible than MTRRs.
1714
1715	  Say N here if you see bootup problems (boot crash, boot hang,
1716	  spontaneous reboots) or a non-working video driver.
1717
1718	  If unsure, say Y.
1719
1720config X86_UMIP
1721	def_bool y
1722	prompt "User Mode Instruction Prevention" if EXPERT
1723	help
1724	  User Mode Instruction Prevention (UMIP) is a security feature in
1725	  some x86 processors. If enabled, a general protection fault is
1726	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1727	  executed in user mode. These instructions unnecessarily expose
1728	  information about the hardware state.
1729
1730	  The vast majority of applications do not use these instructions.
1731	  For the very few that do, software emulation is provided in
1732	  specific cases in protected and virtual-8086 modes. Emulated
1733	  results are dummy.
1734
1735config CC_HAS_IBT
1736	# GCC >= 9 and binutils >= 2.29
1737	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1738	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \
1739		  $(as-instr,endbr64)
1740
1741config X86_CET
1742	def_bool n
1743	help
1744	  CET features configured (Shadow stack or IBT)
1745
1746config X86_KERNEL_IBT
1747	prompt "Indirect Branch Tracking"
1748	def_bool y
1749	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1750	select OBJTOOL
1751	select X86_CET
1752	help
1753	  Build the kernel with support for Indirect Branch Tracking, a
1754	  hardware support course-grain forward-edge Control Flow Integrity
1755	  protection. It enforces that all indirect calls must land on
1756	  an ENDBR instruction, as such, the compiler will instrument the
1757	  code with them to make this happen.
1758
1759	  In addition to building the kernel with IBT, seal all functions that
1760	  are not indirect call targets, avoiding them ever becoming one.
1761
1762	  This requires LTO like objtool runs and will slow down the build. It
1763	  does significantly reduce the number of ENDBR instructions in the
1764	  kernel image.
1765
1766config X86_INTEL_MEMORY_PROTECTION_KEYS
1767	prompt "Memory Protection Keys"
1768	def_bool y
1769	# Note: only available in 64-bit mode
1770	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1771	select ARCH_USES_HIGH_VMA_FLAGS
1772	select ARCH_HAS_PKEYS
1773	help
1774	  Memory Protection Keys provides a mechanism for enforcing
1775	  page-based protections, but without requiring modification of the
1776	  page tables when an application changes protection domains.
1777
1778	  For details, see Documentation/core-api/protection-keys.rst
1779
1780	  If unsure, say y.
1781
1782config ARCH_PKEY_BITS
1783	int
1784	default 4
1785
1786choice
1787	prompt "TSX enable mode"
1788	depends on CPU_SUP_INTEL
1789	default X86_INTEL_TSX_MODE_AUTO
1790	help
1791	  Intel's TSX (Transactional Synchronization Extensions) feature
1792	  allows to optimize locking protocols through lock elision which
1793	  can lead to a noticeable performance boost.
1794
1795	  On the other hand it has been shown that TSX can be exploited
1796	  to form side channel attacks (e.g. TAA) and chances are there
1797	  will be more of those attacks discovered in the future.
1798
1799	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1800	  might override this decision by tsx=on the command line parameter.
1801	  Even with TSX enabled, the kernel will attempt to enable the best
1802	  possible TAA mitigation setting depending on the microcode available
1803	  for the particular machine.
1804
1805	  This option allows to set the default tsx mode between tsx=on, =off
1806	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1807	  details.
1808
1809	  Say off if not sure, auto if TSX is in use but it should be used on safe
1810	  platforms or on if TSX is in use and the security aspect of tsx is not
1811	  relevant.
1812
1813config X86_INTEL_TSX_MODE_OFF
1814	bool "off"
1815	help
1816	  TSX is disabled if possible - equals to tsx=off command line parameter.
1817
1818config X86_INTEL_TSX_MODE_ON
1819	bool "on"
1820	help
1821	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1822	  line parameter.
1823
1824config X86_INTEL_TSX_MODE_AUTO
1825	bool "auto"
1826	help
1827	  TSX is enabled on TSX capable HW that is believed to be safe against
1828	  side channel attacks- equals the tsx=auto command line parameter.
1829endchoice
1830
1831config X86_SGX
1832	bool "Software Guard eXtensions (SGX)"
1833	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1834	select CRYPTO_LIB_SHA256
1835	select MMU_NOTIFIER
1836	select NUMA_KEEP_MEMINFO if NUMA
1837	select XARRAY_MULTI
1838	help
1839	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1840	  that can be used by applications to set aside private regions of code
1841	  and data, referred to as enclaves. An enclave's private memory can
1842	  only be accessed by code running within the enclave. Accesses from
1843	  outside the enclave, including other enclaves, are disallowed by
1844	  hardware.
1845
1846	  If unsure, say N.
1847
1848config X86_USER_SHADOW_STACK
1849	bool "X86 userspace shadow stack"
1850	depends on AS_WRUSS
1851	depends on X86_64
1852	depends on PER_VMA_LOCK
1853	select ARCH_USES_HIGH_VMA_FLAGS
1854	select ARCH_HAS_USER_SHADOW_STACK
1855	select X86_CET
1856	help
1857	  Shadow stack protection is a hardware feature that detects function
1858	  return address corruption.  This helps mitigate ROP attacks.
1859	  Applications must be enabled to use it, and old userspace does not
1860	  get protection "for free".
1861
1862	  CPUs supporting shadow stacks were first released in 2020.
1863
1864	  See Documentation/arch/x86/shstk.rst for more information.
1865
1866	  If unsure, say N.
1867
1868config INTEL_TDX_HOST
1869	bool "Intel Trust Domain Extensions (TDX) host support"
1870	depends on CPU_SUP_INTEL
1871	depends on X86_64
1872	depends on KVM_INTEL
1873	depends on X86_X2APIC
1874	select ARCH_KEEP_MEMBLOCK
1875	depends on CONTIG_ALLOC
1876	depends on X86_MCE
1877	help
1878	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1879	  host and certain physical attacks.  This option enables necessary TDX
1880	  support in the host kernel to run confidential VMs.
1881
1882	  If unsure, say N.
1883
1884config EFI
1885	bool "EFI runtime service support"
1886	depends on ACPI
1887	select UCS2_STRING
1888	select EFI_RUNTIME_WRAPPERS
1889	select ARCH_USE_MEMREMAP_PROT
1890	select EFI_RUNTIME_MAP if KEXEC_CORE
1891	help
1892	  This enables the kernel to use EFI runtime services that are
1893	  available (such as the EFI variable services).
1894
1895	  This option is only useful on systems that have EFI firmware.
1896	  In addition, you should use the latest ELILO loader available
1897	  at <http://elilo.sourceforge.net> in order to take advantage
1898	  of EFI runtime services. However, even with this option, the
1899	  resultant kernel should continue to boot on existing non-EFI
1900	  platforms.
1901
1902config EFI_STUB
1903	bool "EFI stub support"
1904	depends on EFI
1905	select RELOCATABLE
1906	help
1907	  This kernel feature allows a bzImage to be loaded directly
1908	  by EFI firmware without the use of a bootloader.
1909
1910	  See Documentation/admin-guide/efi-stub.rst for more information.
1911
1912config EFI_HANDOVER_PROTOCOL
1913	bool "EFI handover protocol (DEPRECATED)"
1914	depends on EFI_STUB
1915	default y
1916	help
1917	  Select this in order to include support for the deprecated EFI
1918	  handover protocol, which defines alternative entry points into the
1919	  EFI stub.  This is a practice that has no basis in the UEFI
1920	  specification, and requires a priori knowledge on the part of the
1921	  bootloader about Linux/x86 specific ways of passing the command line
1922	  and initrd, and where in memory those assets may be loaded.
1923
1924	  If in doubt, say Y. Even though the corresponding support is not
1925	  present in upstream GRUB or other bootloaders, most distros build
1926	  GRUB with numerous downstream patches applied, and may rely on the
1927	  handover protocol as as result.
1928
1929config EFI_MIXED
1930	bool "EFI mixed-mode support"
1931	depends on EFI_STUB && X86_64
1932	help
1933	  Enabling this feature allows a 64-bit kernel to be booted
1934	  on a 32-bit firmware, provided that your CPU supports 64-bit
1935	  mode.
1936
1937	  Note that it is not possible to boot a mixed-mode enabled
1938	  kernel via the EFI boot stub - a bootloader that supports
1939	  the EFI handover protocol must be used.
1940
1941	  If unsure, say N.
1942
1943config EFI_RUNTIME_MAP
1944	bool "Export EFI runtime maps to sysfs" if EXPERT
1945	depends on EFI
1946	help
1947	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1948	  That memory map is required by the 2nd kernel to set up EFI virtual
1949	  mappings after kexec, but can also be used for debugging purposes.
1950
1951	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1952
1953source "kernel/Kconfig.hz"
1954
1955config ARCH_SUPPORTS_KEXEC
1956	def_bool y
1957
1958config ARCH_SUPPORTS_KEXEC_FILE
1959	def_bool X86_64
1960
1961config ARCH_SELECTS_KEXEC_FILE
1962	def_bool y
1963	depends on KEXEC_FILE
1964	select HAVE_IMA_KEXEC if IMA
1965
1966config ARCH_SUPPORTS_KEXEC_PURGATORY
1967	def_bool y
1968
1969config ARCH_SUPPORTS_KEXEC_SIG
1970	def_bool y
1971
1972config ARCH_SUPPORTS_KEXEC_SIG_FORCE
1973	def_bool y
1974
1975config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
1976	def_bool y
1977
1978config ARCH_SUPPORTS_KEXEC_JUMP
1979	def_bool y
1980
1981config ARCH_SUPPORTS_KEXEC_HANDOVER
1982	def_bool X86_64
1983
1984config ARCH_SUPPORTS_CRASH_DUMP
1985	def_bool X86_64 || (X86_32 && HIGHMEM)
1986
1987config ARCH_DEFAULT_CRASH_DUMP
1988	def_bool y
1989
1990config ARCH_SUPPORTS_CRASH_HOTPLUG
1991	def_bool y
1992
1993config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
1994	def_bool CRASH_RESERVE
1995
1996config PHYSICAL_START
1997	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1998	default "0x1000000"
1999	help
2000	  This gives the physical address where the kernel is loaded.
2001
2002	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2003	  will decompress itself to above physical address and run from there.
2004	  Otherwise, bzImage will run from the address where it has been loaded
2005	  by the boot loader. The only exception is if it is loaded below the
2006	  above physical address, in which case it will relocate itself there.
2007
2008	  In normal kdump cases one does not have to set/change this option
2009	  as now bzImage can be compiled as a completely relocatable image
2010	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2011	  address. This option is mainly useful for the folks who don't want
2012	  to use a bzImage for capturing the crash dump and want to use a
2013	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2014	  to be specifically compiled to run from a specific memory area
2015	  (normally a reserved region) and this option comes handy.
2016
2017	  So if you are using bzImage for capturing the crash dump,
2018	  leave the value here unchanged to 0x1000000 and set
2019	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2020	  for capturing the crash dump change this value to start of
2021	  the reserved region.  In other words, it can be set based on
2022	  the "X" value as specified in the "crashkernel=YM@XM"
2023	  command line boot parameter passed to the panic-ed
2024	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2025	  for more details about crash dumps.
2026
2027	  Usage of bzImage for capturing the crash dump is recommended as
2028	  one does not have to build two kernels. Same kernel can be used
2029	  as production kernel and capture kernel. Above option should have
2030	  gone away after relocatable bzImage support is introduced. But it
2031	  is present because there are users out there who continue to use
2032	  vmlinux for dump capture. This option should go away down the
2033	  line.
2034
2035	  Don't change this unless you know what you are doing.
2036
2037config RELOCATABLE
2038	bool "Build a relocatable kernel"
2039	default y
2040	help
2041	  This builds a kernel image that retains relocation information
2042	  so it can be loaded someplace besides the default 1MB.
2043	  The relocations tend to make the kernel binary about 10% larger,
2044	  but are discarded at runtime.
2045
2046	  One use is for the kexec on panic case where the recovery kernel
2047	  must live at a different physical address than the primary
2048	  kernel.
2049
2050	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2051	  it has been loaded at and the compile time physical address
2052	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2053
2054config RANDOMIZE_BASE
2055	bool "Randomize the address of the kernel image (KASLR)"
2056	depends on RELOCATABLE
2057	default y
2058	help
2059	  In support of Kernel Address Space Layout Randomization (KASLR),
2060	  this randomizes the physical address at which the kernel image
2061	  is decompressed and the virtual address where the kernel
2062	  image is mapped, as a security feature that deters exploit
2063	  attempts relying on knowledge of the location of kernel
2064	  code internals.
2065
2066	  On 64-bit, the kernel physical and virtual addresses are
2067	  randomized separately. The physical address will be anywhere
2068	  between 16MB and the top of physical memory (up to 64TB). The
2069	  virtual address will be randomized from 16MB up to 1GB (9 bits
2070	  of entropy). Note that this also reduces the memory space
2071	  available to kernel modules from 1.5GB to 1GB.
2072
2073	  On 32-bit, the kernel physical and virtual addresses are
2074	  randomized together. They will be randomized from 16MB up to
2075	  512MB (8 bits of entropy).
2076
2077	  Entropy is generated using the RDRAND instruction if it is
2078	  supported. If RDTSC is supported, its value is mixed into
2079	  the entropy pool as well. If neither RDRAND nor RDTSC are
2080	  supported, then entropy is read from the i8254 timer. The
2081	  usable entropy is limited by the kernel being built using
2082	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2083	  minimum of 2MB. As a result, only 10 bits of entropy are
2084	  theoretically possible, but the implementations are further
2085	  limited due to memory layouts.
2086
2087	  If unsure, say Y.
2088
2089# Relocation on x86 needs some additional build support
2090config X86_NEED_RELOCS
2091	def_bool y
2092	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2093	select ARCH_VMLINUX_NEEDS_RELOCS
2094
2095config PHYSICAL_ALIGN
2096	hex "Alignment value to which kernel should be aligned"
2097	default "0x200000"
2098	range 0x2000 0x1000000 if X86_32
2099	range 0x200000 0x1000000 if X86_64
2100	help
2101	  This value puts the alignment restrictions on physical address
2102	  where kernel is loaded and run from. Kernel is compiled for an
2103	  address which meets above alignment restriction.
2104
2105	  If bootloader loads the kernel at a non-aligned address and
2106	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2107	  address aligned to above value and run from there.
2108
2109	  If bootloader loads the kernel at a non-aligned address and
2110	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2111	  load address and decompress itself to the address it has been
2112	  compiled for and run from there. The address for which kernel is
2113	  compiled already meets above alignment restrictions. Hence the
2114	  end result is that kernel runs from a physical address meeting
2115	  above alignment restrictions.
2116
2117	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2118	  this value must be a multiple of 0x200000.
2119
2120	  Don't change this unless you know what you are doing.
2121
2122config RANDOMIZE_MEMORY
2123	bool "Randomize the kernel memory sections"
2124	depends on X86_64
2125	depends on RANDOMIZE_BASE
2126	default RANDOMIZE_BASE
2127	help
2128	  Randomizes the base virtual address of kernel memory sections
2129	  (physical memory mapping, vmalloc & vmemmap). This security feature
2130	  makes exploits relying on predictable memory locations less reliable.
2131
2132	  The order of allocations remains unchanged. Entropy is generated in
2133	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2134	  configuration have in average 30,000 different possible virtual
2135	  addresses for each memory section.
2136
2137	  If unsure, say Y.
2138
2139config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2140	hex "Physical memory mapping padding" if EXPERT
2141	depends on RANDOMIZE_MEMORY
2142	default "0xa" if MEMORY_HOTPLUG
2143	default "0x0"
2144	range 0x1 0x40 if MEMORY_HOTPLUG
2145	range 0x0 0x40
2146	help
2147	  Define the padding in terabytes added to the existing physical
2148	  memory size during kernel memory randomization. It is useful
2149	  for memory hotplug support but reduces the entropy available for
2150	  address randomization.
2151
2152	  If unsure, leave at the default value.
2153
2154config ADDRESS_MASKING
2155	bool "Linear Address Masking support"
2156	depends on X86_64
2157	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2158	help
2159	  Linear Address Masking (LAM) modifies the checking that is applied
2160	  to 64-bit linear addresses, allowing software to use of the
2161	  untranslated address bits for metadata.
2162
2163	  The capability can be used for efficient address sanitizers (ASAN)
2164	  implementation and for optimizations in JITs.
2165
2166config HOTPLUG_CPU
2167	def_bool y
2168	depends on SMP
2169
2170config COMPAT_VDSO
2171	def_bool n
2172	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2173	depends on COMPAT_32
2174	help
2175	  Certain buggy versions of glibc will crash if they are
2176	  presented with a 32-bit vDSO that is not mapped at the address
2177	  indicated in its segment table.
2178
2179	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2180	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2181	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2182	  the only released version with the bug, but OpenSUSE 9
2183	  contains a buggy "glibc 2.3.2".
2184
2185	  The symptom of the bug is that everything crashes on startup, saying:
2186	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2187
2188	  Saying Y here changes the default value of the vdso32 boot
2189	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2190	  This works around the glibc bug but hurts performance.
2191
2192	  If unsure, say N: if you are compiling your own kernel, you
2193	  are unlikely to be using a buggy version of glibc.
2194
2195choice
2196	prompt "vsyscall table for legacy applications"
2197	depends on X86_64
2198	default LEGACY_VSYSCALL_XONLY
2199	help
2200	  Legacy user code that does not know how to find the vDSO expects
2201	  to be able to issue three syscalls by calling fixed addresses in
2202	  kernel space. Since this location is not randomized with ASLR,
2203	  it can be used to assist security vulnerability exploitation.
2204
2205	  This setting can be changed at boot time via the kernel command
2206	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2207	  is deprecated and can only be enabled using the kernel command
2208	  line.
2209
2210	  On a system with recent enough glibc (2.14 or newer) and no
2211	  static binaries, you can say None without a performance penalty
2212	  to improve security.
2213
2214	  If unsure, select "Emulate execution only".
2215
2216	config LEGACY_VSYSCALL_XONLY
2217		bool "Emulate execution only"
2218		help
2219		  The kernel traps and emulates calls into the fixed vsyscall
2220		  address mapping and does not allow reads.  This
2221		  configuration is recommended when userspace might use the
2222		  legacy vsyscall area but support for legacy binary
2223		  instrumentation of legacy code is not needed.  It mitigates
2224		  certain uses of the vsyscall area as an ASLR-bypassing
2225		  buffer.
2226
2227	config LEGACY_VSYSCALL_NONE
2228		bool "None"
2229		help
2230		  There will be no vsyscall mapping at all. This will
2231		  eliminate any risk of ASLR bypass due to the vsyscall
2232		  fixed address mapping. Attempts to use the vsyscalls
2233		  will be reported to dmesg, so that either old or
2234		  malicious userspace programs can be identified.
2235
2236endchoice
2237
2238config CMDLINE_BOOL
2239	bool "Built-in kernel command line"
2240	help
2241	  Allow for specifying boot arguments to the kernel at
2242	  build time.  On some systems (e.g. embedded ones), it is
2243	  necessary or convenient to provide some or all of the
2244	  kernel boot arguments with the kernel itself (that is,
2245	  to not rely on the boot loader to provide them.)
2246
2247	  To compile command line arguments into the kernel,
2248	  set this option to 'Y', then fill in the
2249	  boot arguments in CONFIG_CMDLINE.
2250
2251	  Systems with fully functional boot loaders (i.e. non-embedded)
2252	  should leave this option set to 'N'.
2253
2254config CMDLINE
2255	string "Built-in kernel command string"
2256	depends on CMDLINE_BOOL
2257	default ""
2258	help
2259	  Enter arguments here that should be compiled into the kernel
2260	  image and used at boot time.  If the boot loader provides a
2261	  command line at boot time, it is appended to this string to
2262	  form the full kernel command line, when the system boots.
2263
2264	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2265	  change this behavior.
2266
2267	  In most cases, the command line (whether built-in or provided
2268	  by the boot loader) should specify the device for the root
2269	  file system.
2270
2271config CMDLINE_OVERRIDE
2272	bool "Built-in command line overrides boot loader arguments"
2273	depends on CMDLINE_BOOL && CMDLINE != ""
2274	help
2275	  Set this option to 'Y' to have the kernel ignore the boot loader
2276	  command line, and use ONLY the built-in command line.
2277
2278	  This is used to work around broken boot loaders.  This should
2279	  be set to 'N' under normal conditions.
2280
2281config MODIFY_LDT_SYSCALL
2282	bool "Enable the LDT (local descriptor table)" if EXPERT
2283	default y
2284	help
2285	  Linux can allow user programs to install a per-process x86
2286	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2287	  call.  This is required to run 16-bit or segmented code such as
2288	  DOSEMU or some Wine programs.  It is also used by some very old
2289	  threading libraries.
2290
2291	  Enabling this feature adds a small amount of overhead to
2292	  context switches and increases the low-level kernel attack
2293	  surface.  Disabling it removes the modify_ldt(2) system call.
2294
2295	  Saying 'N' here may make sense for embedded or server kernels.
2296
2297config STRICT_SIGALTSTACK_SIZE
2298	bool "Enforce strict size checking for sigaltstack"
2299	depends on DYNAMIC_SIGFRAME
2300	help
2301	  For historical reasons MINSIGSTKSZ is a constant which became
2302	  already too small with AVX512 support. Add a mechanism to
2303	  enforce strict checking of the sigaltstack size against the
2304	  real size of the FPU frame. This option enables the check
2305	  by default. It can also be controlled via the kernel command
2306	  line option 'strict_sas_size' independent of this config
2307	  switch. Enabling it might break existing applications which
2308	  allocate a too small sigaltstack but 'work' because they
2309	  never get a signal delivered.
2310
2311	  Say 'N' unless you want to really enforce this check.
2312
2313config CFI_AUTO_DEFAULT
2314	bool "Attempt to use FineIBT by default at boot time"
2315	depends on FINEIBT
2316	depends on !RUST || RUSTC_VERSION >= 108800
2317	default y
2318	help
2319	  Attempt to use FineIBT by default at boot time. If enabled,
2320	  this is the same as booting with "cfi=auto". If disabled,
2321	  this is the same as booting with "cfi=kcfi".
2322
2323source "kernel/livepatch/Kconfig"
2324
2325config X86_BUS_LOCK_DETECT
2326	bool "Split Lock Detect and Bus Lock Detect support"
2327	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2328	default y
2329	help
2330	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2331	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2332
2333endmenu
2334
2335config CC_HAS_NAMED_AS
2336	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2337	depends on CC_IS_GCC
2338
2339#
2340# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2341# are incompatible with named address spaces with GCC < 13.3
2342# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2343#
2344
2345config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2346	def_bool y
2347	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2348	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2349
2350config USE_X86_SEG_SUPPORT
2351	def_bool CC_HAS_NAMED_AS
2352	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2353
2354config CC_HAS_SLS
2355	def_bool $(cc-option,-mharden-sls=all)
2356
2357config CC_HAS_RETURN_THUNK
2358	def_bool $(cc-option,-mfunction-return=thunk-extern)
2359
2360config CC_HAS_ENTRY_PADDING
2361	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2362
2363config CC_HAS_KCFI_ARITY
2364	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2365	depends on CC_IS_CLANG && !RUST
2366
2367config FUNCTION_PADDING_CFI
2368	int
2369	default 59 if FUNCTION_ALIGNMENT_64B
2370	default 27 if FUNCTION_ALIGNMENT_32B
2371	default 11 if FUNCTION_ALIGNMENT_16B
2372	default  3 if FUNCTION_ALIGNMENT_8B
2373	default  0
2374
2375# Basically: FUNCTION_ALIGNMENT - 5*CFI
2376# except Kconfig can't do arithmetic :/
2377config FUNCTION_PADDING_BYTES
2378	int
2379	default FUNCTION_PADDING_CFI if CFI
2380	default FUNCTION_ALIGNMENT
2381
2382config CALL_PADDING
2383	def_bool n
2384	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2385	select FUNCTION_ALIGNMENT_16B
2386
2387config FINEIBT
2388	def_bool y
2389	depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE
2390	select CALL_PADDING
2391
2392config FINEIBT_BHI
2393	def_bool y
2394	depends on FINEIBT && CC_HAS_KCFI_ARITY
2395
2396config HAVE_CALL_THUNKS
2397	def_bool y
2398	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2399
2400config CALL_THUNKS
2401	def_bool n
2402	select CALL_PADDING
2403
2404menuconfig CPU_MITIGATIONS
2405	bool "Mitigations for CPU vulnerabilities"
2406	default y
2407	help
2408	  Say Y here to enable options which enable mitigations for hardware
2409	  vulnerabilities (usually related to speculative execution).
2410	  Mitigations can be disabled or restricted to SMT systems at runtime
2411	  via the "mitigations" kernel parameter.
2412
2413	  If you say N, all mitigations will be disabled.  This CANNOT be
2414	  overridden at runtime.
2415
2416	  Say 'Y', unless you really know what you are doing.
2417
2418if CPU_MITIGATIONS
2419
2420config MITIGATION_PAGE_TABLE_ISOLATION
2421	bool "Remove the kernel mapping in user mode"
2422	default y
2423	depends on (X86_64 || X86_PAE)
2424	help
2425	  This feature reduces the number of hardware side channels by
2426	  ensuring that the majority of kernel addresses are not mapped
2427	  into userspace.
2428
2429	  See Documentation/arch/x86/pti.rst for more details.
2430
2431config MITIGATION_RETPOLINE
2432	bool "Avoid speculative indirect branches in kernel"
2433	select OBJTOOL if HAVE_OBJTOOL
2434	default y
2435	help
2436	  Compile kernel with the retpoline compiler options to guard against
2437	  kernel-to-user data leaks by avoiding speculative indirect
2438	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2439	  support for full protection. The kernel may run slower.
2440
2441config MITIGATION_RETHUNK
2442	bool "Enable return-thunks"
2443	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2444	select OBJTOOL if HAVE_OBJTOOL
2445	default y if X86_64
2446	help
2447	  Compile the kernel with the return-thunks compiler option to guard
2448	  against kernel-to-user data leaks by avoiding return speculation.
2449	  Requires a compiler with -mfunction-return=thunk-extern
2450	  support for full protection. The kernel may run slower.
2451
2452config MITIGATION_UNRET_ENTRY
2453	bool "Enable UNRET on kernel entry"
2454	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2455	default y
2456	help
2457	  Compile the kernel with support for the retbleed=unret mitigation.
2458
2459config MITIGATION_CALL_DEPTH_TRACKING
2460	bool "Mitigate RSB underflow with call depth tracking"
2461	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2462	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2463	select CALL_THUNKS
2464	default y
2465	help
2466	  Compile the kernel with call depth tracking to mitigate the Intel
2467	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2468	  by default and needs to be enabled on the kernel command line via the
2469	  retbleed=stuff option. For non-affected systems the overhead of this
2470	  option is marginal as the call depth tracking is using run-time
2471	  generated call thunks in a compiler generated padding area and call
2472	  patching. This increases text size by ~5%. For non affected systems
2473	  this space is unused. On affected SKL systems this results in a
2474	  significant performance gain over the IBRS mitigation.
2475
2476config CALL_THUNKS_DEBUG
2477	bool "Enable call thunks and call depth tracking debugging"
2478	depends on MITIGATION_CALL_DEPTH_TRACKING
2479	select FUNCTION_ALIGNMENT_32B
2480	default n
2481	help
2482	  Enable call/ret counters for imbalance detection and build in
2483	  a noisy dmesg about callthunks generation and call patching for
2484	  trouble shooting. The debug prints need to be enabled on the
2485	  kernel command line with 'debug-callthunks'.
2486	  Only enable this when you are debugging call thunks as this
2487	  creates a noticeable runtime overhead. If unsure say N.
2488
2489config MITIGATION_IBPB_ENTRY
2490	bool "Enable IBPB on kernel entry"
2491	depends on CPU_SUP_AMD && X86_64
2492	default y
2493	help
2494	  Compile the kernel with support for the retbleed=ibpb and
2495	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2496
2497config MITIGATION_IBRS_ENTRY
2498	bool "Enable IBRS on kernel entry"
2499	depends on CPU_SUP_INTEL && X86_64
2500	default y
2501	help
2502	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2503	  This mitigates both spectre_v2 and retbleed at great cost to
2504	  performance.
2505
2506config MITIGATION_SRSO
2507	bool "Mitigate speculative RAS overflow on AMD"
2508	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2509	default y
2510	help
2511	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2512
2513config MITIGATION_SLS
2514	bool "Mitigate Straight-Line-Speculation"
2515	depends on CC_HAS_SLS && X86_64
2516	select OBJTOOL if HAVE_OBJTOOL
2517	default n
2518	help
2519	  Compile the kernel with straight-line-speculation options to guard
2520	  against straight line speculation. The kernel image might be slightly
2521	  larger.
2522
2523config MITIGATION_GDS
2524	bool "Mitigate Gather Data Sampling"
2525	depends on CPU_SUP_INTEL
2526	default y
2527	help
2528	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2529	  vulnerability which allows unprivileged speculative access to data
2530	  which was previously stored in vector registers. The attacker uses gather
2531	  instructions to infer the stale vector register data.
2532
2533config MITIGATION_RFDS
2534	bool "RFDS Mitigation"
2535	depends on CPU_SUP_INTEL
2536	default y
2537	help
2538	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2539	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2540	  allows unprivileged speculative access to stale data previously
2541	  stored in floating point, vector and integer registers.
2542	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2543
2544config MITIGATION_SPECTRE_BHI
2545	bool "Mitigate Spectre-BHB (Branch History Injection)"
2546	depends on CPU_SUP_INTEL
2547	default y
2548	help
2549	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2550	  where the branch history buffer is poisoned to speculatively steer
2551	  indirect branches.
2552	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2553
2554config MITIGATION_MDS
2555	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2556	depends on CPU_SUP_INTEL
2557	default y
2558	help
2559	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2560	  a hardware vulnerability which allows unprivileged speculative access
2561	  to data which is available in various CPU internal buffers.
2562	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2563
2564config MITIGATION_TAA
2565	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2566	depends on CPU_SUP_INTEL
2567	default y
2568	help
2569	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2570	  vulnerability that allows unprivileged speculative access to data
2571	  which is available in various CPU internal buffers by using
2572	  asynchronous aborts within an Intel TSX transactional region.
2573	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2574
2575config MITIGATION_MMIO_STALE_DATA
2576	bool "Mitigate MMIO Stale Data hardware bug"
2577	depends on CPU_SUP_INTEL
2578	default y
2579	help
2580	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2581	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2582	  vulnerabilities that can expose data. The vulnerabilities require the
2583	  attacker to have access to MMIO.
2584	  See also
2585	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2586
2587config MITIGATION_L1TF
2588	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2589	depends on CPU_SUP_INTEL
2590	default y
2591	help
2592	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2593	  hardware vulnerability which allows unprivileged speculative access to data
2594	  available in the Level 1 Data Cache.
2595	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2596
2597config MITIGATION_RETBLEED
2598	bool "Mitigate RETBleed hardware bug"
2599	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2600	default y
2601	help
2602	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2603	  with Return Instructions) vulnerability.  RETBleed is a speculative
2604	  execution attack which takes advantage of microarchitectural behavior
2605	  in many modern microprocessors, similar to Spectre v2. An
2606	  unprivileged attacker can use these flaws to bypass conventional
2607	  memory security restrictions to gain read access to privileged memory
2608	  that would otherwise be inaccessible.
2609
2610config MITIGATION_SPECTRE_V1
2611	bool "Mitigate SPECTRE V1 hardware bug"
2612	default y
2613	help
2614	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2615	  class of side channel attacks that takes advantage of speculative
2616	  execution that bypasses conditional branch instructions used for
2617	  memory access bounds check.
2618	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2619
2620config MITIGATION_SPECTRE_V2
2621	bool "Mitigate SPECTRE V2 hardware bug"
2622	default y
2623	help
2624	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2625	  V2 is a class of side channel attacks that takes advantage of
2626	  indirect branch predictors inside the processor. In Spectre variant 2
2627	  attacks, the attacker can steer speculative indirect branches in the
2628	  victim to gadget code by poisoning the branch target buffer of a CPU
2629	  used for predicting indirect branch addresses.
2630	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2631
2632config MITIGATION_SRBDS
2633	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2634	depends on CPU_SUP_INTEL
2635	default y
2636	help
2637	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2638	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2639	  Sampling (MDS) techniques to infer values returned from special
2640	  register accesses. An unprivileged user can extract values returned
2641	  from RDRAND and RDSEED executed on another core or sibling thread
2642	  using MDS techniques.
2643	  See also
2644	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2645
2646config MITIGATION_SSB
2647	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2648	default y
2649	help
2650	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2651	  hardware security vulnerability and its exploitation takes advantage
2652	  of speculative execution in a similar way to the Meltdown and Spectre
2653	  security vulnerabilities.
2654
2655config MITIGATION_ITS
2656	bool "Enable Indirect Target Selection mitigation"
2657	depends on CPU_SUP_INTEL && X86_64
2658	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2659	select EXECMEM
2660	default y
2661	help
2662	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2663	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2664	  disabled, mitigation cannot be enabled via cmdline.
2665	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2666
2667config MITIGATION_TSA
2668	bool "Mitigate Transient Scheduler Attacks"
2669	depends on CPU_SUP_AMD
2670	default y
2671	help
2672	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2673	  security vulnerability on AMD CPUs which can lead to forwarding of
2674	  invalid info to subsequent instructions and thus can affect their
2675	  timing and thereby cause a leakage.
2676
2677config MITIGATION_VMSCAPE
2678	bool "Mitigate VMSCAPE"
2679	depends on KVM
2680	default y
2681	help
2682	  Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security
2683	  vulnerability on Intel and AMD CPUs that may allow a guest to do
2684	  Spectre v2 style attacks on userspace hypervisor.
2685endif
2686
2687config ARCH_HAS_ADD_PAGES
2688	def_bool y
2689	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2690
2691menu "Power management and ACPI options"
2692
2693config ARCH_HIBERNATION_HEADER
2694	def_bool y
2695	depends on HIBERNATION
2696
2697source "kernel/power/Kconfig"
2698
2699source "drivers/acpi/Kconfig"
2700
2701config X86_APM_BOOT
2702	def_bool y
2703	depends on APM
2704
2705menuconfig APM
2706	tristate "APM (Advanced Power Management) BIOS support"
2707	depends on X86_32 && PM_SLEEP
2708	help
2709	  APM is a BIOS specification for saving power using several different
2710	  techniques. This is mostly useful for battery powered laptops with
2711	  APM compliant BIOSes. If you say Y here, the system time will be
2712	  reset after a RESUME operation, the /proc/apm device will provide
2713	  battery status information, and user-space programs will receive
2714	  notification of APM "events" (e.g. battery status change).
2715
2716	  If you select "Y" here, you can disable actual use of the APM
2717	  BIOS by passing the "apm=off" option to the kernel at boot time.
2718
2719	  Note that the APM support is almost completely disabled for
2720	  machines with more than one CPU.
2721
2722	  In order to use APM, you will need supporting software. For location
2723	  and more information, read <file:Documentation/power/apm-acpi.rst>
2724	  and the Battery Powered Linux mini-HOWTO, available from
2725	  <http://www.tldp.org/docs.html#howto>.
2726
2727	  This driver does not spin down disk drives (see the hdparm(8)
2728	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2729	  VESA-compliant "green" monitors.
2730
2731	  Generally, if you don't have a battery in your machine, there isn't
2732	  much point in using this driver and you should say N. If you get
2733	  random kernel OOPSes or reboots that don't seem to be related to
2734	  anything, try disabling/enabling this option (or disabling/enabling
2735	  APM in your BIOS).
2736
2737	  Some other things you should try when experiencing seemingly random,
2738	  "weird" problems:
2739
2740	  1) make sure that you have enough swap space and that it is
2741	  enabled.
2742	  2) pass the "idle=poll" option to the kernel
2743	  3) pass the "floppy=nodma" option to the kernel
2744	  4) pass the "mem=4M" option to the kernel (thereby disabling
2745	  all but the first 4 MB of RAM)
2746	  5) make sure that the CPU is not over clocked.
2747	  6) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2748	  7) disable the cache from your BIOS settings
2749	  8) install a fan for the video card or exchange video RAM
2750	  9) install a better fan for the CPU
2751	  10) exchange RAM chips
2752	  11) exchange the motherboard.
2753
2754	  To compile this driver as a module, choose M here: the
2755	  module will be called apm.
2756
2757if APM
2758
2759config APM_IGNORE_USER_SUSPEND
2760	bool "Ignore USER SUSPEND"
2761	help
2762	  This option will ignore USER SUSPEND requests. On machines with a
2763	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2764	  series notebooks, it is necessary to say Y because of a BIOS bug.
2765
2766config APM_DO_ENABLE
2767	bool "Enable PM at boot time"
2768	help
2769	  Enable APM features at boot time. From page 36 of the APM BIOS
2770	  specification: "When disabled, the APM BIOS does not automatically
2771	  power manage devices, enter the Standby State, enter the Suspend
2772	  State, or take power saving steps in response to CPU Idle calls."
2773	  This driver will make CPU Idle calls when Linux is idle (unless this
2774	  feature is turned off -- see "Do CPU IDLE calls", below). This
2775	  should always save battery power, but more complicated APM features
2776	  will be dependent on your BIOS implementation. You may need to turn
2777	  this option off if your computer hangs at boot time when using APM
2778	  support, or if it beeps continuously instead of suspending. Turn
2779	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2780	  T400CDT. This is off by default since most machines do fine without
2781	  this feature.
2782
2783config APM_CPU_IDLE
2784	depends on CPU_IDLE
2785	bool "Make CPU Idle calls when idle"
2786	help
2787	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2788	  On some machines, this can activate improved power savings, such as
2789	  a slowed CPU clock rate, when the machine is idle. These idle calls
2790	  are made after the idle loop has run for some length of time (e.g.,
2791	  333 mS). On some machines, this will cause a hang at boot time or
2792	  whenever the CPU becomes idle. (On machines with more than one CPU,
2793	  this option does nothing.)
2794
2795config APM_DISPLAY_BLANK
2796	bool "Enable console blanking using APM"
2797	help
2798	  Enable console blanking using the APM. Some laptops can use this to
2799	  turn off the LCD backlight when the screen blanker of the Linux
2800	  virtual console blanks the screen. Note that this is only used by
2801	  the virtual console screen blanker, and won't turn off the backlight
2802	  when using the X Window system. This also doesn't have anything to
2803	  do with your VESA-compliant power-saving monitor. Further, this
2804	  option doesn't work for all laptops -- it might not turn off your
2805	  backlight at all, or it might print a lot of errors to the console,
2806	  especially if you are using gpm.
2807
2808config APM_ALLOW_INTS
2809	bool "Allow interrupts during APM BIOS calls"
2810	help
2811	  Normally we disable external interrupts while we are making calls to
2812	  the APM BIOS as a measure to lessen the effects of a badly behaving
2813	  BIOS implementation.  The BIOS should reenable interrupts if it
2814	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2815	  many of the newer IBM Thinkpads.  If you experience hangs when you
2816	  suspend, try setting this to Y.  Otherwise, say N.
2817
2818endif # APM
2819
2820source "drivers/cpufreq/Kconfig"
2821
2822source "drivers/cpuidle/Kconfig"
2823
2824source "drivers/idle/Kconfig"
2825
2826endmenu
2827
2828menu "Bus options (PCI etc.)"
2829
2830choice
2831	prompt "PCI access mode"
2832	depends on X86_32 && PCI
2833	default PCI_GOANY
2834	help
2835	  On PCI systems, the BIOS can be used to detect the PCI devices and
2836	  determine their configuration. However, some old PCI motherboards
2837	  have BIOS bugs and may crash if this is done. Also, some embedded
2838	  PCI-based systems don't have any BIOS at all. Linux can also try to
2839	  detect the PCI hardware directly without using the BIOS.
2840
2841	  With this option, you can specify how Linux should detect the
2842	  PCI devices. If you choose "BIOS", the BIOS will be used,
2843	  if you choose "Direct", the BIOS won't be used, and if you
2844	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2845	  If you choose "Any", the kernel will try MMCONFIG, then the
2846	  direct access method and falls back to the BIOS if that doesn't
2847	  work. If unsure, go with the default, which is "Any".
2848
2849config PCI_GOBIOS
2850	bool "BIOS"
2851
2852config PCI_GOMMCONFIG
2853	bool "MMConfig"
2854
2855config PCI_GODIRECT
2856	bool "Direct"
2857
2858config PCI_GOOLPC
2859	bool "OLPC XO-1"
2860	depends on OLPC
2861
2862config PCI_GOANY
2863	bool "Any"
2864
2865endchoice
2866
2867config PCI_BIOS
2868	def_bool y
2869	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2870
2871# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2872config PCI_DIRECT
2873	def_bool y
2874	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2875
2876config PCI_MMCONFIG
2877	bool "Support mmconfig PCI config space access" if X86_64
2878	default y
2879	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2880	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2881	help
2882	  Add support for accessing the PCI configuration space as a memory
2883	  mapped area. It is the recommended method if the system supports
2884	  this (it must have PCI Express and ACPI for it to be available).
2885
2886	  In the unlikely case that enabling this configuration option causes
2887	  problems, the mechanism can be switched off with the 'pci=nommconf'
2888	  command line parameter.
2889
2890	  Say N only if you are sure that your platform does not support this
2891	  access method or you have problems caused by it.
2892
2893	  Say Y otherwise.
2894
2895config PCI_OLPC
2896	def_bool y
2897	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2898
2899config PCI_XEN
2900	def_bool y
2901	depends on PCI && XEN
2902
2903config MMCONF_FAM10H
2904	def_bool y
2905	depends on X86_64 && PCI_MMCONFIG && ACPI
2906
2907config PCI_CNB20LE_QUIRK
2908	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2909	depends on X86_32 && PCI
2910	help
2911	  Read the PCI windows out of the CNB20LE host bridge. This allows
2912	  PCI hotplug to work on systems with the CNB20LE chipset which do
2913	  not have ACPI.
2914
2915	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2916	  most probably only for Pentium III.
2917
2918	  To find out if you have such a chipset, search for a PCI device with
2919	  1166:0009 PCI IDs, for example by executing
2920		lspci -nn | grep '1166:0009'
2921	  The code is inactive if there is none.
2922
2923	  There's no public spec for this chipset, and this functionality
2924	  is known to be incomplete.
2925
2926	  You should say N unless you know you need this.
2927
2928config ISA_BUS
2929	bool "ISA bus support on modern systems" if EXPERT
2930	help
2931	  Expose ISA bus device drivers and options available for selection and
2932	  configuration. Enable this option if your target machine has an ISA
2933	  bus. ISA is an older system, displaced by PCI and newer bus
2934	  architectures -- if your target machine is modern, it probably does
2935	  not have an ISA bus.
2936
2937	  If unsure, say N.
2938
2939# x86_64 have no ISA slots, but can have ISA-style DMA.
2940config ISA_DMA_API
2941	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2942	default y
2943	help
2944	  Enables ISA-style DMA support for devices requiring such controllers.
2945	  If unsure, say Y.
2946
2947if X86_32
2948
2949config ISA
2950	bool "ISA support"
2951	help
2952	  Find out whether you have ISA slots on your motherboard.  ISA is the
2953	  name of a bus system, i.e. the way the CPU talks to the other stuff
2954	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2955	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2956	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2957
2958config SCx200
2959	tristate "NatSemi SCx200 support"
2960	help
2961	  This provides basic support for National Semiconductor's
2962	  (now AMD's) Geode processors.  The driver probes for the
2963	  PCI-IDs of several on-chip devices, so its a good dependency
2964	  for other scx200_* drivers.
2965
2966	  If compiled as a module, the driver is named scx200.
2967
2968config SCx200HR_TIMER
2969	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2970	depends on SCx200
2971	default y
2972	help
2973	  This driver provides a clocksource built upon the on-chip
2974	  27MHz high-resolution timer.  Its also a workaround for
2975	  NSC Geode SC-1100's buggy TSC, which loses time when the
2976	  processor goes idle (as is done by the scheduler).  The
2977	  other workaround is idle=poll boot option.
2978
2979config OLPC
2980	bool "One Laptop Per Child support"
2981	depends on !X86_PAE
2982	select GPIOLIB
2983	select GPIOLIB_LEGACY
2984	select OF
2985	select OF_PROMTREE
2986	select IRQ_DOMAIN
2987	select OLPC_EC
2988	help
2989	  Add support for detecting the unique features of the OLPC
2990	  XO hardware.
2991
2992config OLPC_XO1_PM
2993	bool "OLPC XO-1 Power Management"
2994	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2995	help
2996	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2997
2998config OLPC_XO1_RTC
2999	bool "OLPC XO-1 Real Time Clock"
3000	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3001	help
3002	  Add support for the XO-1 real time clock, which can be used as a
3003	  programmable wakeup source.
3004
3005config OLPC_XO1_SCI
3006	bool "OLPC XO-1 SCI extras"
3007	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3008	depends on INPUT=y
3009	select POWER_SUPPLY
3010	help
3011	  Add support for SCI-based features of the OLPC XO-1 laptop:
3012	   - EC-driven system wakeups
3013	   - Power button
3014	   - Ebook switch
3015	   - Lid switch
3016	   - AC adapter status updates
3017	   - Battery status updates
3018
3019config OLPC_XO15_SCI
3020	bool "OLPC XO-1.5 SCI extras"
3021	depends on OLPC && ACPI
3022	select POWER_SUPPLY
3023	help
3024	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3025	   - EC-driven system wakeups
3026	   - AC adapter status updates
3027	   - Battery status updates
3028
3029config GEODE_COMMON
3030	bool
3031
3032config ALIX
3033	bool "PCEngines ALIX System Support (LED setup)"
3034	depends on GPIO_CS5535=y
3035	select GEODE_COMMON
3036	help
3037	  This option enables system support for the PCEngines ALIX.
3038	  At present this just sets up LEDs for GPIO control on
3039	  ALIX2/3/6 boards.  However, other system specific setup should
3040	  get added here.
3041
3042	  Note: You must still enable the drivers for LED support (LEDS_GPIO)
3043	  to actually use the LEDs
3044
3045	  Note: You have to set alix.force=1 for boards with Award BIOS.
3046
3047config NET5501
3048	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3049	depends on GPIO_CS5535=y
3050	select GEODE_COMMON
3051	help
3052	  This option enables system support for the Soekris Engineering net5501.
3053
3054config GEOS
3055	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3056	depends on GPIO_CS5535=y
3057	select GEODE_COMMON
3058	depends on DMI
3059	help
3060	  This option enables system support for the Traverse Technologies GEOS.
3061
3062config TS5500
3063	bool "Technologic Systems TS-5500 platform support"
3064	depends on MELAN
3065	select CHECK_SIGNATURE
3066	select NEW_LEDS
3067	select LEDS_CLASS
3068	help
3069	  This option enables system support for the Technologic Systems TS-5500.
3070
3071endif # X86_32
3072
3073config AMD_NB
3074	def_bool y
3075	depends on AMD_NODE
3076
3077config AMD_NODE
3078	def_bool y
3079	depends on CPU_SUP_AMD && PCI
3080
3081endmenu
3082
3083menu "Binary Emulations"
3084
3085config IA32_EMULATION
3086	bool "IA32 Emulation"
3087	depends on X86_64
3088	select ARCH_WANT_OLD_COMPAT_IPC
3089	select BINFMT_ELF
3090	select COMPAT_OLD_SIGACTION
3091	help
3092	  Include code to run legacy 32-bit programs under a
3093	  64-bit kernel. You should likely turn this on, unless you're
3094	  100% sure that you don't have any 32-bit programs left.
3095
3096config IA32_EMULATION_DEFAULT_DISABLED
3097	bool "IA32 emulation disabled by default"
3098	default n
3099	depends on IA32_EMULATION
3100	help
3101	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3102	  processes and access to 32-bit syscalls. If unsure, leave it to its
3103	  default value.
3104
3105config X86_X32_ABI
3106	bool "x32 ABI for 64-bit mode"
3107	depends on X86_64
3108	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3109	# compressed debug sections to x86_x32 properly:
3110	# https://github.com/ClangBuiltLinux/linux/issues/514
3111	# https://github.com/ClangBuiltLinux/linux/issues/1141
3112	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3113	help
3114	  Include code to run binaries for the x32 native 32-bit ABI
3115	  for 64-bit processors.  An x32 process gets access to the
3116	  full 64-bit register file and wide data path while leaving
3117	  pointers at 32 bits for smaller memory footprint.
3118
3119config COMPAT_32
3120	def_bool y
3121	depends on IA32_EMULATION || X86_32
3122	select HAVE_UID16
3123	select OLD_SIGSUSPEND3
3124
3125config COMPAT
3126	def_bool y
3127	depends on IA32_EMULATION || X86_X32_ABI
3128
3129config COMPAT_FOR_U64_ALIGNMENT
3130	def_bool y
3131	depends on COMPAT
3132
3133endmenu
3134
3135config HAVE_ATOMIC_IOMAP
3136	def_bool y
3137	depends on X86_32
3138
3139source "arch/x86/kvm/Kconfig"
3140
3141source "arch/x86/Kconfig.cpufeatures"
3142
3143source "arch/x86/Kconfig.assembler"
3144