xref: /linux/arch/x86/Kconfig (revision 3a6455d56bd7c4cfb1ea35ddae052943065e338e)
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_ENABLE_THP_MIGRATION 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_DEVMEM_IS_ALLOWED
84	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
85	select ARCH_HAS_EARLY_DEBUG		if KGDB
86	select ARCH_HAS_ELF_RANDOMIZE
87	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
88	select ARCH_HAS_FAST_MULTIPLIER
89	select ARCH_HAS_FORTIFY_SOURCE
90	select ARCH_HAS_GCOV_PROFILE_ALL
91	select ARCH_HAS_KCOV			if X86_64
92	select ARCH_HAS_KERNEL_FPU_SUPPORT
93	select ARCH_HAS_MEM_ENCRYPT
94	select ARCH_HAS_MEMBARRIER_SYNC_CORE
95	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
96	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
97	select ARCH_HAS_PMEM_API		if X86_64
98	select ARCH_HAS_PREEMPT_LAZY
99	select ARCH_HAS_PTDUMP
100	select ARCH_HAS_PTE_SPECIAL
101	select ARCH_HAS_HW_PTE_YOUNG
102	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
103	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
104	select ARCH_HAS_COPY_MC			if X86_64
105	select ARCH_HAS_SET_MEMORY
106	select ARCH_HAS_SET_DIRECT_MAP
107	select ARCH_HAS_STRICT_KERNEL_RWX
108	select ARCH_HAS_STRICT_MODULE_RWX
109	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
110	select ARCH_HAS_SYSCALL_WRAPPER
111	select ARCH_HAS_UBSAN
112	select ARCH_HAS_DEBUG_WX
113	select ARCH_HAS_ZONE_DMA_SET if EXPERT
114	select ARCH_HAVE_NMI_SAFE_CMPXCHG
115	select ARCH_HAVE_EXTRA_ELF_NOTES
116	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
117	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
118	select ARCH_MIGHT_HAVE_PC_PARPORT
119	select ARCH_MIGHT_HAVE_PC_SERIO
120	select ARCH_STACKWALK
121	select ARCH_SUPPORTS_ACPI
122	select ARCH_SUPPORTS_ATOMIC_RMW
123	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
124	select ARCH_SUPPORTS_HUGETLBFS
125	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
126	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
127	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
128	select ARCH_SUPPORTS_CFI		if X86_64
129	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI
130	select ARCH_SUPPORTS_LTO_CLANG
131	select ARCH_SUPPORTS_LTO_CLANG_THIN
132	select ARCH_SUPPORTS_RT
133	select ARCH_SUPPORTS_AUTOFDO_CLANG
134	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
135	select ARCH_USE_BUILTIN_BSWAP
136	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
137	select ARCH_USE_MEMTEST
138	select ARCH_USE_QUEUED_RWLOCKS
139	select ARCH_USE_QUEUED_SPINLOCKS
140	select ARCH_USE_SYM_ANNOTATIONS
141	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
142	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
143	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
144	select ARCH_WANTS_NO_INSTR
145	select ARCH_WANT_GENERAL_HUGETLB
146	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
147	select ARCH_WANT_LD_ORPHAN_WARN
148	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
149	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
150	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
151	select ARCH_WANTS_THP_SWAP		if X86_64
152	select ARCH_HAS_PARANOID_L1D_FLUSH
153	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
154	select BUILDTIME_TABLE_SORT
155	select CLKEVT_I8253
156	select CLOCKSOURCE_WATCHDOG
157	# Word-size accesses may read uninitialized data past the trailing \0
158	# in strings and cause false KMSAN reports.
159	select DCACHE_WORD_ACCESS		if !KMSAN
160	select DYNAMIC_SIGFRAME
161	select EDAC_ATOMIC_SCRUB
162	select EDAC_SUPPORT
163	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
164	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
165	select GENERIC_CLOCKEVENTS_MIN_ADJUST
166	select GENERIC_CMOS_UPDATE
167	select GENERIC_CPU_AUTOPROBE
168	select GENERIC_CPU_DEVICES
169	select GENERIC_CPU_VULNERABILITIES
170	select GENERIC_EARLY_IOREMAP
171	select GENERIC_ENTRY
172	select GENERIC_IOMAP
173	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
174	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
175	select GENERIC_IRQ_MIGRATION		if SMP
176	select GENERIC_IRQ_PROBE
177	select GENERIC_IRQ_RESERVATION_MODE
178	select GENERIC_IRQ_SHOW
179	select GENERIC_PENDING_IRQ		if SMP
180	select GENERIC_SMP_IDLE_THREAD
181	select GENERIC_TIME_VSYSCALL
182	select GENERIC_GETTIMEOFDAY
183	select GENERIC_VDSO_OVERFLOW_PROTECT
184	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
185	select HARDIRQS_SW_RESEND
186	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
187	select HAS_IOPORT
188	select HAVE_ACPI_APEI			if ACPI
189	select HAVE_ACPI_APEI_NMI		if ACPI
190	select HAVE_ALIGNED_STRUCT_PAGE
191	select HAVE_ARCH_AUDITSYSCALL
192	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
193	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
194	select HAVE_ARCH_JUMP_LABEL
195	select HAVE_ARCH_JUMP_LABEL_RELATIVE
196	select HAVE_ARCH_KASAN			if X86_64
197	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
198	select HAVE_ARCH_KFENCE
199	select HAVE_ARCH_KMSAN			if X86_64
200	select HAVE_ARCH_KGDB
201	select HAVE_ARCH_KSTACK_ERASE
202	select HAVE_ARCH_MMAP_RND_BITS		if MMU
203	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
204	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
205	select HAVE_ARCH_PREL32_RELOCATIONS
206	select HAVE_ARCH_SECCOMP_FILTER
207	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
208	select HAVE_ARCH_TRACEHOOK
209	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
210	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
211	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
212	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
213	select HAVE_ARCH_VMAP_STACK		if X86_64
214	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
215	select HAVE_ARCH_WITHIN_STACK_FRAMES
216	select HAVE_ASM_MODVERSIONS
217	select HAVE_CMPXCHG_DOUBLE
218	select HAVE_CMPXCHG_LOCAL
219	select HAVE_CONTEXT_TRACKING_USER		if X86_64
220	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
221	select HAVE_C_RECORDMCOUNT
222	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
223	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
224	select HAVE_BUILDTIME_MCOUNT_SORT
225	select HAVE_DEBUG_KMEMLEAK
226	select HAVE_DMA_CONTIGUOUS
227	select HAVE_DYNAMIC_FTRACE
228	select HAVE_DYNAMIC_FTRACE_WITH_REGS
229	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
230	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
231	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
232	select HAVE_DYNAMIC_FTRACE_WITH_JMP	if X86_64
233	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
234	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
235	select HAVE_EBPF_JIT
236	select HAVE_EFFICIENT_UNALIGNED_ACCESS
237	select HAVE_EISA			if X86_32
238	select HAVE_EXIT_THREAD
239	select HAVE_GENERIC_TIF_BITS
240	select HAVE_GUP_FAST
241	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
242	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
243	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
244	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
245	select HAVE_FUNCTION_TRACER
246	select HAVE_GCC_PLUGINS
247	select HAVE_HW_BREAKPOINT
248	select HAVE_IOREMAP_PROT
249	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
250	select HAVE_IRQ_TIME_ACCOUNTING
251	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
252	select HAVE_KERNEL_BZIP2
253	select HAVE_KERNEL_GZIP
254	select HAVE_KERNEL_LZ4
255	select HAVE_KERNEL_LZMA
256	select HAVE_KERNEL_LZO
257	select HAVE_KERNEL_XZ
258	select HAVE_KERNEL_ZSTD
259	select HAVE_KPROBES
260	select HAVE_KPROBES_ON_FTRACE
261	select HAVE_FUNCTION_ERROR_INJECTION
262	select HAVE_KRETPROBES
263	select HAVE_RETHOOK
264	select HAVE_KLP_BUILD			if X86_64
265	select HAVE_LIVEPATCH			if X86_64
266	select HAVE_MIXED_BREAKPOINTS_REGS
267	select HAVE_MOD_ARCH_SPECIFIC
268	select HAVE_MOVE_PMD
269	select HAVE_MOVE_PUD
270	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
271	select HAVE_NMI
272	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
273	select HAVE_OBJTOOL			if X86_64
274	select HAVE_OPTPROBES
275	select HAVE_PAGE_SIZE_4KB
276	select HAVE_PCSPKR_PLATFORM
277	select HAVE_PERF_EVENTS
278	select HAVE_PERF_EVENTS_NMI
279	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
280	select HAVE_PCI
281	select HAVE_PERF_REGS
282	select HAVE_PERF_USER_STACK_DUMP
283	select ASYNC_KERNEL_PGTABLE_FREE	if IOMMU_SVA
284	select MMU_GATHER_RCU_TABLE_FREE
285	select MMU_GATHER_MERGE_VMAS
286	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
287	select HAVE_REGS_AND_STACK_ACCESS_API
288	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
289	select HAVE_FUNCTION_ARG_ACCESS_API
290	select HAVE_SETUP_PER_CPU_AREA
291	select HAVE_SOFTIRQ_ON_OWN_STACK
292	select HAVE_STACKPROTECTOR
293	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
294	select HAVE_STATIC_CALL
295	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
296	select HAVE_PREEMPT_DYNAMIC_CALL
297	select HAVE_RSEQ
298	select HAVE_RUST			if X86_64
299	select HAVE_SYSCALL_TRACEPOINTS
300	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
301	select HAVE_UNSTABLE_SCHED_CLOCK
302	select HAVE_UNWIND_USER_FP		if X86_64
303	select HAVE_USER_RETURN_NOTIFIER
304	select HAVE_GENERIC_VDSO
305	select VDSO_GETRANDOM			if X86_64
306	select HOTPLUG_PARALLEL			if SMP && X86_64
307	select HOTPLUG_SMT			if SMP
308	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
309	select IRQ_FORCED_THREADING
310	select LOCK_MM_AND_FIND_VMA
311	select NEED_PER_CPU_EMBED_FIRST_CHUNK
312	select NEED_PER_CPU_PAGE_FIRST_CHUNK
313	select NEED_SG_DMA_LENGTH
314	select NUMA_MEMBLKS			if NUMA
315	select PCI_DOMAINS			if PCI
316	select PCI_LOCKLESS_CONFIG		if PCI
317	select PERF_EVENTS
318	select RTC_LIB
319	select RTC_MC146818_LIB
320	select SPARSE_IRQ
321	select SYSCTL_EXCEPTION_TRACE
322	select THREAD_INFO_IN_TASK
323	select TRACE_IRQFLAGS_SUPPORT
324	select TRACE_IRQFLAGS_NMI_SUPPORT
325	select USER_STACKTRACE_SUPPORT
326	select HAVE_ARCH_KCSAN			if X86_64
327	select PROC_PID_ARCH_STATUS		if PROC_FS
328	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
329	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
330	select FUNCTION_ALIGNMENT_4B
331	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
332	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
333	select ARCH_SUPPORTS_SCHED_SMT		if SMP
334	select SCHED_SMT			if SMP
335	select ARCH_SUPPORTS_SCHED_CLUSTER	if SMP
336	select ARCH_SUPPORTS_SCHED_MC		if SMP
337	select HAVE_SINGLE_FTRACE_DIRECT_OPS	if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS
338
339config INSTRUCTION_DECODER
340	def_bool y
341	depends on KPROBES || PERF_EVENTS || UPROBES
342
343config OUTPUT_FORMAT
344	string
345	default "elf32-i386" if X86_32
346	default "elf64-x86-64" if X86_64
347
348config LOCKDEP_SUPPORT
349	def_bool y
350
351config STACKTRACE_SUPPORT
352	def_bool y
353
354config MMU
355	def_bool y
356
357config ARCH_MMAP_RND_BITS_MIN
358	default 28 if 64BIT
359	default 8
360
361config ARCH_MMAP_RND_BITS_MAX
362	default 32 if 64BIT
363	default 16
364
365config ARCH_MMAP_RND_COMPAT_BITS_MIN
366	default 8
367
368config ARCH_MMAP_RND_COMPAT_BITS_MAX
369	default 16
370
371config SBUS
372	bool
373
374config GENERIC_ISA_DMA
375	def_bool y
376	depends on ISA_DMA_API
377
378config GENERIC_CSUM
379	bool
380	default y if KMSAN || KASAN
381
382config GENERIC_BUG
383	def_bool y
384	depends on BUG
385	select GENERIC_BUG_RELATIVE_POINTERS
386
387config GENERIC_BUG_RELATIVE_POINTERS
388	bool
389
390config ARCH_MAY_HAVE_PC_FDC
391	def_bool y
392	depends on ISA_DMA_API
393
394config GENERIC_CALIBRATE_DELAY
395	def_bool y
396
397config ARCH_HAS_CPU_RELAX
398	def_bool y
399
400config ARCH_HIBERNATION_POSSIBLE
401	def_bool y
402
403config ARCH_SUSPEND_POSSIBLE
404	def_bool y
405
406config AUDIT_ARCH
407	def_bool y if X86_64
408
409config KASAN_SHADOW_OFFSET
410	hex
411	depends on KASAN
412	default 0xdffffc0000000000
413
414config HAVE_INTEL_TXT
415	def_bool y
416	depends on INTEL_IOMMU && ACPI
417
418config ARCH_SUPPORTS_UPROBES
419	def_bool y
420
421config FIX_EARLYCON_MEM
422	def_bool y
423
424config DYNAMIC_PHYSICAL_MASK
425	bool
426
427config PGTABLE_LEVELS
428	int
429	default 5 if X86_64
430	default 3 if X86_PAE
431	default 2
432
433menu "Processor type and features"
434
435config SMP
436	bool "Symmetric multi-processing support"
437	help
438	  This enables support for systems with more than one CPU. If you have
439	  a system with only one CPU, say N. If you have a system with more
440	  than one CPU, say Y.
441
442	  If you say N here, the kernel will run on uni- and multiprocessor
443	  machines, but will use only one CPU of a multiprocessor machine. If
444	  you say Y here, the kernel will run on many, but not all,
445	  uniprocessor machines. On a uniprocessor machine, the kernel
446	  will run faster if you say N here.
447
448	  Note that if you say Y here and choose architecture "586" or
449	  "Pentium" under "Processor family", the kernel will not work on 486
450	  architectures. Similarly, multiprocessor kernels for the "PPro"
451	  architecture may not work on all Pentium based boards.
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, try to 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 X86_TSC
690	depends on PCI
691	depends on PCI_GOANY
692	depends on X86_IO_APIC
693	select IOSF_MBI
694	select INTEL_IMR
695	select COMMON_CLK
696	help
697	  Select to include support for Quark X1000 SoC.
698	  Say Y here if you have a Quark based system such as the Arduino
699	  compatible Intel Galileo.
700
701config X86_RDC321X
702	bool "RDC R-321x SoC"
703	depends on X86_32
704	depends on X86_EXTENDED_PLATFORM
705	select M486
706	select X86_REBOOTFIXUPS
707	help
708	  This option is needed for RDC R-321x system-on-chip, also known
709	  as R-8610-(G).
710	  If you don't have one of these chips, you should say N here.
711
712config X86_INTEL_LPSS
713	bool "Intel Low Power Subsystem Support"
714	depends on X86 && ACPI && PCI
715	select COMMON_CLK
716	select PINCTRL
717	select IOSF_MBI
718	help
719	  Select to build support for Intel Low Power Subsystem such as
720	  found on Intel Lynxpoint PCH. Selecting this option enables
721	  things like clock tree (common clock framework) and pincontrol
722	  which are needed by the LPSS peripheral drivers.
723
724config X86_AMD_PLATFORM_DEVICE
725	bool "AMD ACPI2Platform devices support"
726	depends on ACPI
727	select COMMON_CLK
728	select PINCTRL
729	help
730	  Select to interpret AMD specific ACPI device to platform device
731	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
732	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
733	  implemented under PINCTRL subsystem.
734
735config IOSF_MBI
736	tristate "Intel SoC IOSF Sideband support for SoC platforms"
737	depends on PCI
738	help
739	  This option enables sideband register access support for Intel SoC
740	  platforms. On these platforms the IOSF sideband is used in lieu of
741	  MSR's for some register accesses, mostly but not limited to thermal
742	  and power. Drivers may query the availability of this device to
743	  determine if they need the sideband in order to work on these
744	  platforms. The sideband is available on the following SoC products.
745	  This list is not meant to be exclusive.
746	   - BayTrail
747	   - Braswell
748	   - Quark
749
750	  You should say Y if you are running a kernel on one of these SoC's.
751
752config IOSF_MBI_DEBUG
753	bool "Enable IOSF sideband access through debugfs"
754	depends on IOSF_MBI && DEBUG_FS
755	help
756	  Select this option to expose the IOSF sideband access registers (MCR,
757	  MDR, MCRX) through debugfs to write and read register information from
758	  different units on the SoC. This is most useful for obtaining device
759	  state information for debug and analysis. As this is a general access
760	  mechanism, users of this option would have specific knowledge of the
761	  device they want to access.
762
763	  If you don't require the option or are in doubt, say N.
764
765config X86_SUPPORTS_MEMORY_FAILURE
766	def_bool y
767	# MCE code calls memory_failure():
768	depends on X86_MCE
769	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
770	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
771	depends on X86_64 || !SPARSEMEM
772	select ARCH_SUPPORTS_MEMORY_FAILURE
773
774config X86_32_IRIS
775	tristate "Eurobraille/Iris poweroff module"
776	depends on X86_32
777	help
778	  The Iris machines from EuroBraille do not have APM or ACPI support
779	  to shut themselves down properly.  A special I/O sequence is
780	  needed to do so, which is what this module does at
781	  kernel shutdown.
782
783	  This is only for Iris machines from EuroBraille.
784
785	  If unused, say N.
786
787config SCHED_OMIT_FRAME_POINTER
788	def_bool y
789	prompt "Single-depth WCHAN output"
790	depends on X86
791	help
792	  Calculate simpler /proc/<PID>/wchan values. If this option
793	  is disabled then wchan values will recurse back to the
794	  caller function. This provides more accurate wchan values,
795	  at the expense of slightly more scheduling overhead.
796
797	  If in doubt, say "Y".
798
799menuconfig HYPERVISOR_GUEST
800	bool "Linux guest support"
801	help
802	  Say Y here to enable options for running Linux under various hyper-
803	  visors. This option enables basic hypervisor detection and platform
804	  setup.
805
806	  If you say N, all options in this submenu will be skipped and
807	  disabled, and Linux guest support won't be built in.
808
809if HYPERVISOR_GUEST
810
811config PARAVIRT
812	bool "Enable paravirtualization code"
813	depends on HAVE_STATIC_CALL
814	select HAVE_PV_STEAL_CLOCK_GEN
815	help
816	  This changes the kernel so it can modify itself when it is run
817	  under a hypervisor, potentially improving performance significantly
818	  over full virtualization.  However, when run without a hypervisor
819	  the kernel is theoretically slower and slightly larger.
820
821config PARAVIRT_XXL
822	bool
823	depends on X86_64
824	select ARCH_HAS_LAZY_MMU_MODE
825
826config PARAVIRT_SPINLOCKS
827	bool "Paravirtualization layer for spinlocks"
828	depends on PARAVIRT && SMP
829	help
830	  Paravirtualized spinlocks allow a pvops backend to replace the
831	  spinlock implementation with something virtualization-friendly
832	  (for example, block the virtual CPU rather than spinning).
833
834	  It has a minimal impact on native kernels and gives a nice performance
835	  benefit on paravirtualized KVM / Xen kernels.
836
837	  If you are unsure how to answer this question, answer Y.
838
839config X86_HV_CALLBACK_VECTOR
840	def_bool n
841
842source "arch/x86/xen/Kconfig"
843
844config KVM_GUEST
845	bool "KVM Guest support (including kvmclock)"
846	depends on PARAVIRT
847	select PARAVIRT_CLOCK
848	select ARCH_CPUIDLE_HALTPOLL
849	select X86_HV_CALLBACK_VECTOR
850	default y
851	help
852	  This option enables various optimizations for running under the KVM
853	  hypervisor. It includes a paravirtualized clock, so that instead
854	  of relying on a PIT (or probably other) emulation by the
855	  underlying device model, the host provides the guest with
856	  timing infrastructure such as time of day, and system time
857
858config ARCH_CPUIDLE_HALTPOLL
859	def_bool n
860	prompt "Disable host haltpoll when loading haltpoll driver"
861	help
862	  If virtualized under KVM, disable host haltpoll.
863
864config PVH
865	bool "Support for running PVH guests"
866	help
867	  This option enables the PVH entry point for guest virtual machines
868	  as specified in the x86/HVM direct boot ABI.
869
870config PARAVIRT_TIME_ACCOUNTING
871	bool "Paravirtual steal time accounting"
872	depends on PARAVIRT
873	help
874	  Select this option to enable fine granularity task steal time
875	  accounting. Time spent executing other tasks in parallel with
876	  the current vCPU is discounted from the vCPU power. To account for
877	  that, there can be a small performance impact.
878
879	  If in doubt, say N here.
880
881config PARAVIRT_CLOCK
882	bool
883
884config JAILHOUSE_GUEST
885	bool "Jailhouse non-root cell support"
886	depends on X86_64 && PCI
887	select X86_PM_TIMER
888	help
889	  This option allows to run Linux as guest in a Jailhouse non-root
890	  cell. You can leave this option disabled if you only want to start
891	  Jailhouse and run Linux afterwards in the root cell.
892
893config ACRN_GUEST
894	bool "ACRN Guest support"
895	depends on X86_64
896	select X86_HV_CALLBACK_VECTOR
897	help
898	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
899	  a flexible, lightweight reference open-source hypervisor, built with
900	  real-time and safety-criticality in mind. It is built for embedded
901	  IOT with small footprint and real-time features. More details can be
902	  found in https://projectacrn.org/.
903
904config BHYVE_GUEST
905	bool "Bhyve (BSD Hypervisor) Guest support"
906	depends on X86_64
907	help
908	  This option allows to run Linux to recognise when it is running as a
909	  guest in the Bhyve hypervisor, and to support more than 255 vCPUs when
910	  when doing so. More details about Bhyve can be found at https://bhyve.org
911	  and https://wiki.freebsd.org/bhyve/.
912
913config INTEL_TDX_GUEST
914	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
915	depends on X86_64 && CPU_SUP_INTEL
916	depends on X86_X2APIC
917	depends on EFI_STUB
918	depends on PARAVIRT
919	select ARCH_HAS_CC_PLATFORM
920	select X86_MEM_ENCRYPT
921	select X86_MCE
922	select UNACCEPTED_MEMORY
923	help
924	  Support running as a guest under Intel TDX.  Without this support,
925	  the guest kernel can not boot or run under TDX.
926	  TDX includes memory encryption and integrity capabilities
927	  which protect the confidentiality and integrity of guest
928	  memory contents and CPU state. TDX guests are protected from
929	  some attacks from the VMM.
930
931endif # HYPERVISOR_GUEST
932
933source "arch/x86/Kconfig.cpu"
934
935config HPET_TIMER
936	def_bool X86_64
937	prompt "HPET Timer Support" if X86_32
938	help
939	  Use the IA-PC HPET (High Precision Event Timer) to manage
940	  time in preference to the PIT and RTC, if a HPET is
941	  present.
942	  HPET is the next generation timer replacing legacy 8254s.
943	  The HPET provides a stable time base on SMP
944	  systems, unlike the TSC, but it is more expensive to access,
945	  as it is off-chip.  The interface used is documented
946	  in the HPET spec, revision 1.
947
948	  You can safely choose Y here.  However, HPET will only be
949	  activated if the platform and the BIOS support this feature.
950	  Otherwise the 8254 will be used for timing services.
951
952	  Choose N to continue using the legacy 8254 timer.
953
954config HPET_EMULATE_RTC
955	def_bool y
956	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
957
958# Mark as expert because too many people got it wrong.
959# The code disables itself when not needed.
960config DMI
961	default y
962	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
963	bool "Enable DMI scanning" if EXPERT
964	help
965	  Enabled scanning of DMI to identify machine quirks. Say Y
966	  here unless you have verified that your setup is not
967	  affected by entries in the DMI blacklist. Required by PNP
968	  BIOS code.
969
970config GART_IOMMU
971	bool "Old AMD GART IOMMU support"
972	select IOMMU_HELPER
973	select SWIOTLB
974	depends on X86_64 && PCI && AMD_NB
975	help
976	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
977	  GART based hardware IOMMUs.
978
979	  The GART supports full DMA access for devices with 32-bit access
980	  limitations, on systems with more than 3 GB. This is usually needed
981	  for USB, sound, many IDE/SATA chipsets and some other devices.
982
983	  Newer systems typically have a modern AMD IOMMU, supported via
984	  the CONFIG_AMD_IOMMU=y config option.
985
986	  In normal configurations this driver is only active when needed:
987	  there's more than 3 GB of memory and the system contains a
988	  32-bit limited device.
989
990	  If unsure, say Y.
991
992config BOOT_VESA_SUPPORT
993	bool
994	help
995	  If true, at least one selected framebuffer driver can take advantage
996	  of VESA video modes set at an early boot stage via the vga= parameter.
997
998config MAXSMP
999	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
1000	depends on X86_64 && SMP && DEBUG_KERNEL
1001	select CPUMASK_OFFSTACK
1002	help
1003	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
1004	  If unsure, say N.
1005
1006#
1007# The maximum number of CPUs supported:
1008#
1009# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
1010# and which can be configured interactively in the
1011# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
1012#
1013# The ranges are different on 32-bit and 64-bit kernels, depending on
1014# hardware capabilities and scalability features of the kernel.
1015#
1016# ( If MAXSMP is enabled we just use the highest possible value and disable
1017#   interactive configuration. )
1018#
1019
1020config NR_CPUS_RANGE_BEGIN
1021	int
1022	default NR_CPUS_RANGE_END if MAXSMP
1023	default    1 if !SMP
1024	default    2
1025
1026config NR_CPUS_RANGE_END
1027	int
1028	depends on X86_32
1029	default    8 if  SMP
1030	default    1 if !SMP
1031
1032config NR_CPUS_RANGE_END
1033	int
1034	depends on X86_64
1035	default 8192 if  SMP && CPUMASK_OFFSTACK
1036	default  512 if  SMP && !CPUMASK_OFFSTACK
1037	default    1 if !SMP
1038
1039config NR_CPUS_DEFAULT
1040	int
1041	depends on X86_32
1042	default    8 if  SMP
1043	default    1 if !SMP
1044
1045config NR_CPUS_DEFAULT
1046	int
1047	depends on X86_64
1048	default 8192 if  MAXSMP
1049	default   64 if  SMP
1050	default    1 if !SMP
1051
1052config NR_CPUS
1053	int "Maximum number of CPUs" if SMP && !MAXSMP
1054	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1055	default NR_CPUS_DEFAULT
1056	help
1057	  This allows you to specify the maximum number of CPUs which this
1058	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1059	  supported value is 8192, otherwise the maximum value is 512.  The
1060	  minimum value which makes sense is 2.
1061
1062	  This is purely to save memory: each supported CPU adds about 8KB
1063	  to the kernel image.
1064
1065config SCHED_MC_PRIO
1066	bool "CPU core priorities scheduler support"
1067	depends on SCHED_MC
1068	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1069	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1070	select CPU_FREQ
1071	default y
1072	help
1073	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1074	  core ordering determined at manufacturing time, which allows
1075	  certain cores to reach higher turbo frequencies (when running
1076	  single threaded workloads) than others.
1077
1078	  Enabling this kernel feature teaches the scheduler about
1079	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1080	  scheduler's CPU selection logic accordingly, so that higher
1081	  overall system performance can be achieved.
1082
1083	  This feature will have no effect on CPUs without this feature.
1084
1085	  If unsure say Y here.
1086
1087config UP_LATE_INIT
1088	def_bool y
1089	depends on !SMP && X86_LOCAL_APIC
1090
1091config X86_UP_APIC
1092	bool "Local APIC support on uniprocessors" if !PCI_MSI
1093	default PCI_MSI
1094	depends on X86_32 && !SMP
1095	help
1096	  A local APIC (Advanced Programmable Interrupt Controller) is an
1097	  integrated interrupt controller in the CPU. If you have a single-CPU
1098	  system which has a processor with a local APIC, you can say Y here to
1099	  enable and use it. If you say Y here even though your machine doesn't
1100	  have a local APIC, then the kernel will still run with no slowdown at
1101	  all. The local APIC supports CPU-generated self-interrupts (timer,
1102	  performance counters), and the NMI watchdog which detects hard
1103	  lockups.
1104
1105config X86_UP_IOAPIC
1106	bool "IO-APIC support on uniprocessors"
1107	depends on X86_UP_APIC
1108	help
1109	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1110	  SMP-capable replacement for PC-style interrupt controllers. Most
1111	  SMP systems and many recent uniprocessor systems have one.
1112
1113	  If you have a single-CPU system with an IO-APIC, you can say Y here
1114	  to use it. If you say Y here even though your machine doesn't have
1115	  an IO-APIC, then the kernel will still run with no slowdown at all.
1116
1117config X86_LOCAL_APIC
1118	def_bool y
1119	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1120	select IRQ_DOMAIN_HIERARCHY
1121
1122config ACPI_MADT_WAKEUP
1123	def_bool y
1124	depends on X86_64
1125	depends on ACPI
1126	depends on SMP
1127	depends on X86_LOCAL_APIC
1128
1129config X86_IO_APIC
1130	def_bool y
1131	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1132
1133config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1134	bool "Reroute for broken boot IRQs"
1135	depends on X86_IO_APIC
1136	help
1137	  This option enables a workaround that fixes a source of
1138	  spurious interrupts. This is recommended when threaded
1139	  interrupt handling is used on systems where the generation of
1140	  superfluous "boot interrupts" cannot be disabled.
1141
1142	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1143	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1144	  kernel does during interrupt handling). On chipsets where this
1145	  boot IRQ generation cannot be disabled, this workaround keeps
1146	  the original IRQ line masked so that only the equivalent "boot
1147	  IRQ" is delivered to the CPUs. The workaround also tells the
1148	  kernel to set up the IRQ handler on the boot IRQ line. In this
1149	  way only one interrupt is delivered to the kernel. Otherwise
1150	  the spurious second interrupt may cause the kernel to bring
1151	  down (vital) interrupt lines.
1152
1153	  Only affects "broken" chipsets. Interrupt sharing may be
1154	  increased on these systems.
1155
1156config X86_MCE
1157	bool "Machine Check / overheating reporting"
1158	select GENERIC_ALLOCATOR
1159	default y
1160	help
1161	  Machine Check support allows the processor to notify the
1162	  kernel if it detects a problem (e.g. overheating, data corruption).
1163	  The action the kernel takes depends on the severity of the problem,
1164	  ranging from warning messages to halting the machine.
1165
1166config X86_MCELOG_LEGACY
1167	bool "Support for deprecated /dev/mcelog character device"
1168	depends on X86_MCE
1169	help
1170	  Enable support for /dev/mcelog which is needed by the old mcelog
1171	  userspace logging daemon. Consider switching to the new generation
1172	  rasdaemon solution.
1173
1174config X86_MCE_INTEL
1175	def_bool y
1176	prompt "Intel MCE features"
1177	depends on X86_MCE && X86_LOCAL_APIC
1178	help
1179	  Additional support for intel specific MCE features such as
1180	  the thermal monitor.
1181
1182config X86_MCE_AMD
1183	def_bool y
1184	prompt "AMD MCE features"
1185	depends on X86_MCE && X86_LOCAL_APIC
1186	help
1187	  Additional support for AMD specific MCE features such as
1188	  the DRAM Error Threshold.
1189
1190config X86_ANCIENT_MCE
1191	bool "Support for old Pentium 5 / WinChip machine checks"
1192	depends on X86_32 && X86_MCE
1193	help
1194	  Include support for machine check handling on old Pentium 5 or WinChip
1195	  systems. These typically need to be enabled explicitly on the command
1196	  line.
1197
1198config X86_MCE_THRESHOLD
1199	depends on X86_MCE_AMD || X86_MCE_INTEL
1200	def_bool y
1201
1202config X86_MCE_INJECT
1203	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1204	tristate "Machine check injector support"
1205	help
1206	  Provide support for injecting machine checks for testing purposes.
1207	  If you don't know what a machine check is and you don't do kernel
1208	  QA it is safe to say n.
1209
1210source "arch/x86/events/Kconfig"
1211
1212config X86_LEGACY_VM86
1213	bool "Legacy VM86 support"
1214	depends on X86_32
1215	help
1216	  This option allows user programs to put the CPU into V8086
1217	  mode, which is an 80286-era approximation of 16-bit real mode.
1218
1219	  Some very old versions of X and/or vbetool require this option
1220	  for user mode setting.  Similarly, DOSEMU will use it if
1221	  available to accelerate real mode DOS programs.  However, any
1222	  recent version of DOSEMU, X, or vbetool should be fully
1223	  functional even without kernel VM86 support, as they will all
1224	  fall back to software emulation. Nevertheless, if you are using
1225	  a 16-bit DOS program where 16-bit performance matters, vm86
1226	  mode might be faster than emulation and you might want to
1227	  enable this option.
1228
1229	  Note that any app that works on a 64-bit kernel is unlikely to
1230	  need this option, as 64-bit kernels don't, and can't, support
1231	  V8086 mode. This option is also unrelated to 16-bit protected
1232	  mode and is not needed to run most 16-bit programs under Wine.
1233
1234	  Enabling this option increases the complexity of the kernel
1235	  and slows down exception handling a tiny bit.
1236
1237	  If unsure, say N here.
1238
1239config VM86
1240	bool
1241	default X86_LEGACY_VM86
1242
1243config X86_16BIT
1244	bool "Enable support for 16-bit segments" if EXPERT
1245	default y
1246	depends on MODIFY_LDT_SYSCALL
1247	help
1248	  This option is required by programs like Wine to run 16-bit
1249	  protected mode legacy code on x86 processors.  Disabling
1250	  this option saves about 300 bytes on i386, or around 6K text
1251	  plus 16K runtime memory on x86-64,
1252
1253config X86_ESPFIX32
1254	def_bool y
1255	depends on X86_16BIT && X86_32
1256
1257config X86_ESPFIX64
1258	def_bool y
1259	depends on X86_16BIT && X86_64
1260
1261config X86_VSYSCALL_EMULATION
1262	bool "Enable vsyscall emulation" if EXPERT
1263	default y
1264	depends on X86_64
1265	help
1266	  This enables emulation of the legacy vsyscall page.  Disabling
1267	  it is roughly equivalent to booting with vsyscall=none, except
1268	  that it will also disable the helpful warning if a program
1269	  tries to use a vsyscall.  With this option set to N, offending
1270	  programs will just segfault, citing addresses of the form
1271	  0xffffffffff600?00.
1272
1273	  This option is required by many programs built before 2013, and
1274	  care should be used even with newer programs if set to N.
1275
1276	  Disabling this option saves about 7K of kernel size and
1277	  possibly 4K of additional runtime pagetable memory.
1278
1279config X86_IOPL_IOPERM
1280	bool "IOPERM and IOPL Emulation"
1281	default y
1282	help
1283	  This enables the ioperm() and iopl() syscalls which are necessary
1284	  for legacy applications.
1285
1286	  Legacy IOPL support is an overbroad mechanism which allows user
1287	  space aside of accessing all 65536 I/O ports also to disable
1288	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1289	  capabilities and permission from potentially active security
1290	  modules.
1291
1292	  The emulation restricts the functionality of the syscall to
1293	  only allowing the full range I/O port access, but prevents the
1294	  ability to disable interrupts from user space which would be
1295	  granted if the hardware IOPL mechanism would be used.
1296
1297config TOSHIBA
1298	tristate "Toshiba Laptop support"
1299	depends on X86_32
1300	help
1301	  This adds a driver to safely access the System Management Mode of
1302	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1303	  not work on models with a Phoenix BIOS. The System Management Mode
1304	  is used to set the BIOS and power saving options on Toshiba portables.
1305
1306	  For information on utilities to make use of this driver see the
1307	  Toshiba Linux utilities web site at:
1308	  <http://www.buzzard.org.uk/toshiba/>.
1309
1310	  Say Y if you intend to run this kernel on a Toshiba portable.
1311	  Say N otherwise.
1312
1313config X86_REBOOTFIXUPS
1314	bool "Enable X86 board specific fixups for reboot"
1315	depends on X86_32
1316	help
1317	  This enables chipset and/or board specific fixups to be done
1318	  in order to get reboot to work correctly. This is only needed on
1319	  some combinations of hardware and BIOS. The symptom, for which
1320	  this config is intended, is when reboot ends with a stalled/hung
1321	  system.
1322
1323	  Currently, the only fixup is for the Geode machines using
1324	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1325
1326	  Say Y if you want to enable the fixup. Currently, it's safe to
1327	  enable this option even if you don't need it.
1328	  Say N otherwise.
1329
1330config MICROCODE
1331	def_bool y
1332	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1333	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1334
1335config MICROCODE_INITRD32
1336	def_bool y
1337	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1338
1339config MICROCODE_LATE_LOADING
1340	bool "Late microcode loading (DANGEROUS)"
1341	default n
1342	depends on MICROCODE && SMP
1343	help
1344	  Loading microcode late, when the system is up and executing instructions
1345	  is a tricky business and should be avoided if possible. Just the sequence
1346	  of synchronizing all cores and SMT threads is one fragile dance which does
1347	  not guarantee that cores might not softlock after the loading. Therefore,
1348	  use this at your own risk. Late loading taints the kernel unless the
1349	  microcode header indicates that it is safe for late loading via the
1350	  minimal revision check. This minimal revision check can be enforced on
1351	  the kernel command line with "microcode=force_minrev".
1352
1353config MICROCODE_LATE_FORCE_MINREV
1354	bool "Enforce late microcode loading minimal revision check"
1355	default n
1356	depends on MICROCODE_LATE_LOADING
1357	help
1358	  To prevent that users load microcode late which modifies already
1359	  in use features, newer microcode patches have a minimum revision field
1360	  in the microcode header, which tells the kernel which minimum
1361	  revision must be active in the CPU to safely load that new microcode
1362	  late into the running system. If disabled the check will not
1363	  be enforced but the kernel will be tainted when the minimal
1364	  revision check fails.
1365
1366	  This minimal revision check can also be controlled via the
1367	  "microcode=force_minrev" parameter on the kernel command line.
1368
1369	  If unsure say Y.
1370
1371config MICROCODE_DBG
1372	bool "Enable microcode loader debugging"
1373	default n
1374	depends on MICROCODE
1375	help
1376	  Enable code which allows to debug the microcode loader. When running
1377	  in a guest the patch loading is simulated but everything else
1378	  related to patch parsing and handling is done as on baremetal with
1379	  the purpose of debugging solely the software side of things. On
1380	  baremetal, it simply dumps additional debugging information during
1381	  normal operation.
1382
1383	  You almost certainly want to say n here.
1384
1385config X86_MSR
1386	tristate "/dev/cpu/*/msr - Model-specific register support"
1387	help
1388	  This device gives privileged processes access to the x86
1389	  Model-Specific Registers (MSRs).  It is a character device with
1390	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1391	  MSR accesses are directed to a specific CPU on multi-processor
1392	  systems.
1393
1394config X86_CPUID
1395	tristate "/dev/cpu/*/cpuid - CPU information support"
1396	help
1397	  This device gives processes access to the x86 CPUID instruction to
1398	  be executed on a specific processor.  It is a character device
1399	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1400	  /dev/cpu/31/cpuid.
1401
1402config HIGHMEM4G
1403	bool "High Memory Support"
1404	depends on X86_32
1405	help
1406	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1407	  However, the address space of 32-bit x86 processors is only 4
1408	  Gigabytes large. That means that, if you have a large amount of
1409	  physical memory, not all of it can be "permanently mapped" by the
1410	  kernel. The physical memory that's not permanently mapped is called
1411	  "high memory".
1412
1413	  If you are compiling a kernel which will never run on a machine with
1414	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1415	  choice and suitable for most users). This will result in a "3GB/1GB"
1416	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1417	  space and the remaining part of the 4GB virtual memory space is used
1418	  by the kernel to permanently map as much physical memory as
1419	  possible.
1420
1421	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1422	  answer "Y" here.
1423
1424	  If unsure, say N.
1425
1426choice
1427	prompt "Memory split" if EXPERT
1428	default VMSPLIT_3G
1429	depends on X86_32
1430	help
1431	  Select the desired split between kernel and user memory.
1432
1433	  If the address range available to the kernel is less than the
1434	  physical memory installed, the remaining memory will be available
1435	  as "high memory". Accessing high memory is a little more costly
1436	  than low memory, as it needs to be mapped into the kernel first.
1437	  Note that increasing the kernel address space limits the range
1438	  available to user programs, making the address space there
1439	  tighter.  Selecting anything other than the default 3G/1G split
1440	  will also likely make your kernel incompatible with binary-only
1441	  kernel modules.
1442
1443	  If you are not absolutely sure what you are doing, leave this
1444	  option alone!
1445
1446	config VMSPLIT_3G
1447		bool "3G/1G user/kernel split"
1448	config VMSPLIT_3G_OPT
1449		depends on !X86_PAE
1450		bool "3G/1G user/kernel split (for full 1G low memory)"
1451	config VMSPLIT_2G
1452		bool "2G/2G user/kernel split"
1453	config VMSPLIT_2G_OPT
1454		depends on !X86_PAE
1455		bool "2G/2G user/kernel split (for full 2G low memory)"
1456	config VMSPLIT_1G
1457		bool "1G/3G user/kernel split"
1458endchoice
1459
1460config PAGE_OFFSET
1461	hex
1462	default 0xB0000000 if VMSPLIT_3G_OPT
1463	default 0x80000000 if VMSPLIT_2G
1464	default 0x78000000 if VMSPLIT_2G_OPT
1465	default 0x40000000 if VMSPLIT_1G
1466	default 0xC0000000
1467	depends on X86_32
1468
1469config HIGHMEM
1470	def_bool HIGHMEM4G
1471
1472config X86_PAE
1473	bool "PAE (Physical Address Extension) Support"
1474	depends on X86_32 && X86_HAVE_PAE
1475	select PHYS_ADDR_T_64BIT
1476	help
1477	  PAE is required for NX support, and furthermore enables
1478	  larger swapspace support for non-overcommit purposes. It
1479	  has the cost of more pagetable lookup overhead, and also
1480	  consumes more pagetable space per process.
1481
1482config X86_DIRECT_GBPAGES
1483	def_bool y
1484	depends on X86_64
1485	help
1486	  Certain kernel features effectively disable kernel
1487	  linear 1 GB mappings (even if the CPU otherwise
1488	  supports them), so don't confuse the user by printing
1489	  that we have them enabled.
1490
1491config X86_CPA_STATISTICS
1492	bool "Enable statistic for Change Page Attribute"
1493	depends on DEBUG_FS
1494	help
1495	  Expose statistics about the Change Page Attribute mechanism, which
1496	  helps to determine the effectiveness of preserving large and huge
1497	  page mappings when mapping protections are changed.
1498
1499config X86_MEM_ENCRYPT
1500	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1501	select DYNAMIC_PHYSICAL_MASK
1502	def_bool n
1503
1504config AMD_MEM_ENCRYPT
1505	bool "AMD Secure Memory Encryption (SME) support"
1506	depends on X86_64 && CPU_SUP_AMD
1507	depends on EFI_STUB
1508	select DMA_COHERENT_POOL
1509	select ARCH_USE_MEMREMAP_PROT
1510	select INSTRUCTION_DECODER
1511	select ARCH_HAS_CC_PLATFORM
1512	select X86_MEM_ENCRYPT
1513	select UNACCEPTED_MEMORY
1514	select CRYPTO_LIB_AESGCM
1515	help
1516	  Say yes to enable support for the encryption of system memory.
1517	  This requires an AMD processor that supports Secure Memory
1518	  Encryption (SME).
1519
1520# Common NUMA Features
1521config NUMA
1522	bool "NUMA Memory Allocation and Scheduler Support"
1523	depends on SMP
1524	depends on X86_64
1525	select USE_PERCPU_NUMA_NODE_ID
1526	select OF_NUMA if OF
1527	help
1528	  Enable NUMA (Non-Uniform Memory Access) support.
1529
1530	  The kernel will try to allocate memory used by a CPU on the
1531	  local memory controller of the CPU and add some more
1532	  NUMA awareness to the kernel.
1533
1534	  For 64-bit this is recommended if the system is Intel Core i7
1535	  (or later), AMD Opteron, or EM64T NUMA.
1536
1537	  Otherwise, you should say N.
1538
1539config AMD_NUMA
1540	def_bool y
1541	prompt "Old style AMD Opteron NUMA detection"
1542	depends on X86_64 && NUMA && PCI
1543	help
1544	  Enable AMD NUMA node topology detection.  You should say Y here if
1545	  you have a multi processor AMD system. This uses an old method to
1546	  read the NUMA configuration directly from the builtin Northbridge
1547	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1548	  which also takes priority if both are compiled in.
1549
1550config X86_64_ACPI_NUMA
1551	def_bool y
1552	prompt "ACPI NUMA detection"
1553	depends on X86_64 && NUMA && ACPI && PCI
1554	select ACPI_NUMA
1555	help
1556	  Enable ACPI SRAT based node topology detection.
1557
1558config NODES_SHIFT
1559	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1560	range 1 10
1561	default "10" if MAXSMP
1562	default "6" if X86_64
1563	default "3"
1564	depends on NUMA
1565	help
1566	  Specify the maximum number of NUMA Nodes available on the target
1567	  system.  Increases memory reserved to accommodate various tables.
1568
1569config ARCH_FLATMEM_ENABLE
1570	def_bool y
1571	depends on X86_32 && !NUMA
1572
1573config ARCH_SPARSEMEM_ENABLE
1574	def_bool y
1575	select SPARSEMEM_STATIC if X86_32
1576	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1577
1578config ARCH_SPARSEMEM_DEFAULT
1579	def_bool X86_64 || (NUMA && X86_32)
1580
1581config ARCH_SELECT_MEMORY_MODEL
1582	def_bool y
1583	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1584
1585config ARCH_MEMORY_PROBE
1586	bool "Enable sysfs memory/probe interface"
1587	depends on MEMORY_HOTPLUG
1588	help
1589	  This option enables a sysfs memory/probe interface for testing.
1590	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1591	  If you are unsure how to answer this question, answer N.
1592
1593config ARCH_PROC_KCORE_TEXT
1594	def_bool y
1595	depends on X86_64 && PROC_KCORE
1596
1597config ILLEGAL_POINTER_VALUE
1598	hex
1599	default 0 if X86_32
1600	default 0xdead000000000000 if X86_64
1601
1602config X86_PMEM_LEGACY_DEVICE
1603	bool
1604
1605config X86_PMEM_LEGACY
1606	tristate "Support non-standard NVDIMMs and ADR protected memory"
1607	depends on PHYS_ADDR_T_64BIT
1608	depends on BLK_DEV
1609	select X86_PMEM_LEGACY_DEVICE
1610	select NUMA_KEEP_MEMINFO if NUMA
1611	select LIBNVDIMM
1612	help
1613	  Treat memory marked using the non-standard e820 type of 12 as used
1614	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1615	  The kernel will offer these regions to the 'pmem' driver so
1616	  they can be used for persistent storage.
1617
1618	  Say Y if unsure.
1619
1620config X86_CHECK_BIOS_CORRUPTION
1621	bool "Check for low memory corruption"
1622	help
1623	  Periodically check for memory corruption in low memory, which
1624	  is suspected to be caused by BIOS.  Even when enabled in the
1625	  configuration, it is disabled at runtime.  Enable it by
1626	  setting "memory_corruption_check=1" on the kernel command
1627	  line.  By default it scans the low 64k of memory every 60
1628	  seconds; see the memory_corruption_check_size and
1629	  memory_corruption_check_period parameters in
1630	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1631
1632	  When enabled with the default parameters, this option has
1633	  almost no overhead, as it reserves a relatively small amount
1634	  of memory and scans it infrequently.  It both detects corruption
1635	  and prevents it from affecting the running system.
1636
1637	  It is, however, intended as a diagnostic tool; if repeatable
1638	  BIOS-originated corruption always affects the same memory,
1639	  you can use memmap= to prevent the kernel from using that
1640	  memory.
1641
1642config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1643	bool "Set the default setting of memory_corruption_check"
1644	depends on X86_CHECK_BIOS_CORRUPTION
1645	default y
1646	help
1647	  Set whether the default state of memory_corruption_check is
1648	  on or off.
1649
1650config MATH_EMULATION
1651	bool
1652	depends on MODIFY_LDT_SYSCALL
1653	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1654	help
1655	  Linux can emulate a math coprocessor (used for floating point
1656	  operations) if you don't have one. 486DX and Pentium processors have
1657	  a math coprocessor built in, 486SX and 386 do not, unless you added
1658	  a 487DX or 387, respectively. (The messages during boot time can
1659	  give you some hints here ["man dmesg"].) Everyone needs either a
1660	  coprocessor or this emulation.
1661
1662	  If you don't have a math coprocessor, you need to say Y here; if you
1663	  say Y here even though you have a coprocessor, the coprocessor will
1664	  be used nevertheless. (This behavior can be changed with the kernel
1665	  command line option "no387", which comes handy if your coprocessor
1666	  is broken. Try "man bootparam" or see the documentation of your boot
1667	  loader (lilo or loadlin) about how to pass options to the kernel at
1668	  boot time.) This means that it is a good idea to say Y here if you
1669	  intend to use this kernel on different machines.
1670
1671	  More information about the internals of the Linux math coprocessor
1672	  emulation can be found in <file:arch/x86/math-emu/README>.
1673
1674	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1675	  kernel, it won't hurt.
1676
1677config MTRR
1678	def_bool y
1679	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1680	help
1681	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1682	  the Memory Type Range Registers (MTRRs) may be used to control
1683	  processor access to memory ranges. This is most useful if you have
1684	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1685	  allows bus write transfers to be combined into a larger transfer
1686	  before bursting over the PCI/AGP bus. This can increase performance
1687	  of image write operations 2.5 times or more. Saying Y here creates a
1688	  /proc/mtrr file which may be used to manipulate your processor's
1689	  MTRRs. Typically the X server should use this.
1690
1691	  This code has a reasonably generic interface so that similar
1692	  control registers on other processors can be easily supported
1693	  as well:
1694
1695	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1696	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1697	  these, the ARRs are used to emulate the MTRRs.
1698	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1699	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1700	  write-combining. All of these processors are supported by this code
1701	  and it makes sense to say Y here if you have one of them.
1702
1703	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1704	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1705	  can lead to all sorts of problems, so it's good to say Y here.
1706
1707	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1708	  just add about 9 KB to your kernel.
1709
1710	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1711
1712config MTRR_SANITIZER
1713	def_bool y
1714	prompt "MTRR cleanup support"
1715	depends on MTRR
1716	help
1717	  Convert MTRR layout from continuous to discrete, so X drivers can
1718	  add writeback entries.
1719
1720	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1721	  The largest mtrr entry size for a continuous block can be set with
1722	  mtrr_chunk_size.
1723
1724	  If unsure, say Y.
1725
1726config MTRR_SANITIZER_ENABLE_DEFAULT
1727	int "MTRR cleanup enable value (0-1)"
1728	range 0 1
1729	default "0"
1730	depends on MTRR_SANITIZER
1731	help
1732	  Enable mtrr cleanup default value
1733
1734config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1735	int "MTRR cleanup spare reg num (0-7)"
1736	range 0 7
1737	default "1"
1738	depends on MTRR_SANITIZER
1739	help
1740	  mtrr cleanup spare entries default, it can be changed via
1741	  mtrr_spare_reg_nr=N on the kernel command line.
1742
1743config X86_PAT
1744	def_bool y
1745	prompt "x86 PAT support" if EXPERT
1746	depends on MTRR
1747	select ARCH_USES_PG_ARCH_2
1748	help
1749	  Use PAT attributes to setup page level cache control.
1750
1751	  PATs are the modern equivalents of MTRRs and are much more
1752	  flexible than MTRRs.
1753
1754	  Say N here if you see bootup problems (boot crash, boot hang,
1755	  spontaneous reboots) or a non-working video driver.
1756
1757	  If unsure, say Y.
1758
1759config X86_UMIP
1760	def_bool y
1761	prompt "User Mode Instruction Prevention" if EXPERT
1762	help
1763	  User Mode Instruction Prevention (UMIP) is a security feature in
1764	  some x86 processors. If enabled, a general protection fault is
1765	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1766	  executed in user mode. These instructions unnecessarily expose
1767	  information about the hardware state.
1768
1769	  The vast majority of applications do not use these instructions.
1770	  For the very few that do, software emulation is provided in
1771	  specific cases in protected and virtual-8086 modes. Emulated
1772	  results are dummy.
1773
1774config CC_HAS_IBT
1775	# GCC >= 9 and binutils >= 2.29
1776	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1777	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \
1778		  $(as-instr,endbr64)
1779
1780config X86_CET
1781	def_bool n
1782	help
1783	  CET features configured (Shadow stack or IBT)
1784
1785config X86_KERNEL_IBT
1786	prompt "Indirect Branch Tracking"
1787	def_bool y
1788	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1789	select OBJTOOL
1790	select X86_CET
1791	help
1792	  Build the kernel with support for Indirect Branch Tracking, a
1793	  hardware support course-grain forward-edge Control Flow Integrity
1794	  protection. It enforces that all indirect calls must land on
1795	  an ENDBR instruction, as such, the compiler will instrument the
1796	  code with them to make this happen.
1797
1798	  In addition to building the kernel with IBT, seal all functions that
1799	  are not indirect call targets, avoiding them ever becoming one.
1800
1801	  This requires LTO like objtool runs and will slow down the build. It
1802	  does significantly reduce the number of ENDBR instructions in the
1803	  kernel image.
1804
1805config X86_INTEL_MEMORY_PROTECTION_KEYS
1806	prompt "Memory Protection Keys"
1807	def_bool y
1808	# Note: only available in 64-bit mode
1809	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1810	select ARCH_USES_HIGH_VMA_FLAGS
1811	select ARCH_HAS_PKEYS
1812	help
1813	  Memory Protection Keys provides a mechanism for enforcing
1814	  page-based protections, but without requiring modification of the
1815	  page tables when an application changes protection domains.
1816
1817	  For details, see Documentation/core-api/protection-keys.rst
1818
1819	  If unsure, say y.
1820
1821config ARCH_PKEY_BITS
1822	int
1823	default 4
1824
1825choice
1826	prompt "TSX enable mode"
1827	depends on CPU_SUP_INTEL
1828	default X86_INTEL_TSX_MODE_AUTO
1829	help
1830	  Intel's TSX (Transactional Synchronization Extensions) feature
1831	  allows to optimize locking protocols through lock elision which
1832	  can lead to a noticeable performance boost.
1833
1834	  On the other hand it has been shown that TSX can be exploited
1835	  to form side channel attacks (e.g. TAA) and chances are there
1836	  will be more of those attacks discovered in the future.
1837
1838	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1839	  might override this decision by tsx=on the command line parameter.
1840	  Even with TSX enabled, the kernel will attempt to enable the best
1841	  possible TAA mitigation setting depending on the microcode available
1842	  for the particular machine.
1843
1844	  This option allows to set the default tsx mode between tsx=on, =off
1845	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1846	  details.
1847
1848	  Say off if not sure, auto if TSX is in use but it should be used on safe
1849	  platforms or on if TSX is in use and the security aspect of tsx is not
1850	  relevant.
1851
1852config X86_INTEL_TSX_MODE_OFF
1853	bool "off"
1854	help
1855	  TSX is disabled if possible - equals to tsx=off command line parameter.
1856
1857config X86_INTEL_TSX_MODE_ON
1858	bool "on"
1859	help
1860	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1861	  line parameter.
1862
1863config X86_INTEL_TSX_MODE_AUTO
1864	bool "auto"
1865	help
1866	  TSX is enabled on TSX capable HW that is believed to be safe against
1867	  side channel attacks- equals the tsx=auto command line parameter.
1868endchoice
1869
1870config X86_SGX
1871	bool "Software Guard eXtensions (SGX)"
1872	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1873	select CRYPTO_LIB_SHA256
1874	select MMU_NOTIFIER
1875	select NUMA_KEEP_MEMINFO if NUMA
1876	select XARRAY_MULTI
1877	help
1878	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1879	  that can be used by applications to set aside private regions of code
1880	  and data, referred to as enclaves. An enclave's private memory can
1881	  only be accessed by code running within the enclave. Accesses from
1882	  outside the enclave, including other enclaves, are disallowed by
1883	  hardware.
1884
1885	  If unsure, say N.
1886
1887config X86_USER_SHADOW_STACK
1888	bool "X86 userspace shadow stack"
1889	depends on AS_WRUSS
1890	depends on X86_64
1891	select ARCH_USES_HIGH_VMA_FLAGS
1892	select ARCH_HAS_USER_SHADOW_STACK
1893	select X86_CET
1894	help
1895	  Shadow stack protection is a hardware feature that detects function
1896	  return address corruption.  This helps mitigate ROP attacks.
1897	  Applications must be enabled to use it, and old userspace does not
1898	  get protection "for free".
1899
1900	  CPUs supporting shadow stacks were first released in 2020.
1901
1902	  See Documentation/arch/x86/shstk.rst for more information.
1903
1904	  If unsure, say N.
1905
1906config INTEL_TDX_HOST
1907	bool "Intel Trust Domain Extensions (TDX) host support"
1908	depends on CPU_SUP_INTEL
1909	depends on X86_64
1910	depends on KVM_INTEL
1911	depends on X86_X2APIC
1912	select ARCH_KEEP_MEMBLOCK
1913	depends on CONTIG_ALLOC
1914	depends on X86_MCE
1915	help
1916	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1917	  host and certain physical attacks.  This option enables necessary TDX
1918	  support in the host kernel to run confidential VMs.
1919
1920	  If unsure, say N.
1921
1922config EFI
1923	bool "EFI runtime service support"
1924	depends on ACPI
1925	select UCS2_STRING
1926	select EFI_RUNTIME_WRAPPERS
1927	select ARCH_USE_MEMREMAP_PROT
1928	select EFI_RUNTIME_MAP if KEXEC_CORE
1929	help
1930	  This enables the kernel to use EFI runtime services that are
1931	  available (such as the EFI variable services).
1932
1933	  This option is only useful on systems that have EFI firmware.
1934	  In addition, you should use the latest ELILO loader available
1935	  at <http://elilo.sourceforge.net> in order to take advantage
1936	  of EFI runtime services. However, even with this option, the
1937	  resultant kernel should continue to boot on existing non-EFI
1938	  platforms.
1939
1940config EFI_STUB
1941	bool "EFI stub support"
1942	depends on EFI
1943	select RELOCATABLE
1944	help
1945	  This kernel feature allows a bzImage to be loaded directly
1946	  by EFI firmware without the use of a bootloader.
1947
1948	  See Documentation/admin-guide/efi-stub.rst for more information.
1949
1950config EFI_HANDOVER_PROTOCOL
1951	bool "EFI handover protocol (DEPRECATED)"
1952	depends on EFI_STUB
1953	default y
1954	help
1955	  Select this in order to include support for the deprecated EFI
1956	  handover protocol, which defines alternative entry points into the
1957	  EFI stub.  This is a practice that has no basis in the UEFI
1958	  specification, and requires a priori knowledge on the part of the
1959	  bootloader about Linux/x86 specific ways of passing the command line
1960	  and initrd, and where in memory those assets may be loaded.
1961
1962	  If in doubt, say Y. Even though the corresponding support is not
1963	  present in upstream GRUB or other bootloaders, most distros build
1964	  GRUB with numerous downstream patches applied, and may rely on the
1965	  handover protocol as as result.
1966
1967config EFI_MIXED
1968	bool "EFI mixed-mode support"
1969	depends on EFI_STUB && X86_64
1970	help
1971	  Enabling this feature allows a 64-bit kernel to be booted
1972	  on a 32-bit firmware, provided that your CPU supports 64-bit
1973	  mode.
1974
1975	  Note that it is not possible to boot a mixed-mode enabled
1976	  kernel via the EFI boot stub - a bootloader that supports
1977	  the EFI handover protocol must be used.
1978
1979	  If unsure, say N.
1980
1981config EFI_RUNTIME_MAP
1982	bool "Export EFI runtime maps to sysfs" if EXPERT
1983	depends on EFI
1984	help
1985	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1986	  That memory map is required by the 2nd kernel to set up EFI virtual
1987	  mappings after kexec, but can also be used for debugging purposes.
1988
1989	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1990
1991source "kernel/Kconfig.hz"
1992
1993config ARCH_SUPPORTS_KEXEC
1994	def_bool y
1995
1996config ARCH_SUPPORTS_KEXEC_FILE
1997	def_bool X86_64
1998
1999config ARCH_SELECTS_KEXEC_FILE
2000	def_bool y
2001	depends on KEXEC_FILE
2002	select HAVE_IMA_KEXEC if IMA
2003
2004config ARCH_SUPPORTS_KEXEC_PURGATORY
2005	def_bool y
2006
2007config ARCH_SUPPORTS_KEXEC_SIG
2008	def_bool y
2009
2010config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2011	def_bool y
2012
2013config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2014	def_bool y
2015
2016config ARCH_SUPPORTS_KEXEC_JUMP
2017	def_bool y
2018
2019config ARCH_SUPPORTS_KEXEC_HANDOVER
2020	def_bool X86_64
2021
2022config ARCH_SUPPORTS_CRASH_DUMP
2023	def_bool X86_64 || (X86_32 && HIGHMEM)
2024
2025config ARCH_DEFAULT_CRASH_DUMP
2026	def_bool y
2027
2028config ARCH_SUPPORTS_CRASH_HOTPLUG
2029	def_bool y
2030
2031config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2032	def_bool CRASH_RESERVE
2033
2034config PHYSICAL_START
2035	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2036	default "0x1000000"
2037	help
2038	  This gives the physical address where the kernel is loaded.
2039
2040	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2041	  will decompress itself to above physical address and run from there.
2042	  Otherwise, bzImage will run from the address where it has been loaded
2043	  by the boot loader. The only exception is if it is loaded below the
2044	  above physical address, in which case it will relocate itself there.
2045
2046	  In normal kdump cases one does not have to set/change this option
2047	  as now bzImage can be compiled as a completely relocatable image
2048	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2049	  address. This option is mainly useful for the folks who don't want
2050	  to use a bzImage for capturing the crash dump and want to use a
2051	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2052	  to be specifically compiled to run from a specific memory area
2053	  (normally a reserved region) and this option comes handy.
2054
2055	  So if you are using bzImage for capturing the crash dump,
2056	  leave the value here unchanged to 0x1000000 and set
2057	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2058	  for capturing the crash dump change this value to start of
2059	  the reserved region.  In other words, it can be set based on
2060	  the "X" value as specified in the "crashkernel=YM@XM"
2061	  command line boot parameter passed to the panic-ed
2062	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2063	  for more details about crash dumps.
2064
2065	  Usage of bzImage for capturing the crash dump is recommended as
2066	  one does not have to build two kernels. Same kernel can be used
2067	  as production kernel and capture kernel. Above option should have
2068	  gone away after relocatable bzImage support is introduced. But it
2069	  is present because there are users out there who continue to use
2070	  vmlinux for dump capture. This option should go away down the
2071	  line.
2072
2073	  Don't change this unless you know what you are doing.
2074
2075config RELOCATABLE
2076	bool "Build a relocatable kernel"
2077	default y
2078	help
2079	  This builds a kernel image that retains relocation information
2080	  so it can be loaded someplace besides the default 1MB.
2081	  The relocations tend to make the kernel binary about 10% larger,
2082	  but are discarded at runtime.
2083
2084	  One use is for the kexec on panic case where the recovery kernel
2085	  must live at a different physical address than the primary
2086	  kernel.
2087
2088	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2089	  it has been loaded at and the compile time physical address
2090	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2091
2092config RANDOMIZE_BASE
2093	bool "Randomize the address of the kernel image (KASLR)"
2094	depends on RELOCATABLE
2095	default y
2096	help
2097	  In support of Kernel Address Space Layout Randomization (KASLR),
2098	  this randomizes the physical address at which the kernel image
2099	  is decompressed and the virtual address where the kernel
2100	  image is mapped, as a security feature that deters exploit
2101	  attempts relying on knowledge of the location of kernel
2102	  code internals.
2103
2104	  On 64-bit, the kernel physical and virtual addresses are
2105	  randomized separately. The physical address will be anywhere
2106	  between 16MB and the top of physical memory (up to 64TB). The
2107	  virtual address will be randomized from 16MB up to 1GB (9 bits
2108	  of entropy). Note that this also reduces the memory space
2109	  available to kernel modules from 1.5GB to 1GB.
2110
2111	  On 32-bit, the kernel physical and virtual addresses are
2112	  randomized together. They will be randomized from 16MB up to
2113	  512MB (8 bits of entropy).
2114
2115	  Entropy is generated using the RDRAND instruction if it is
2116	  supported. If RDTSC is supported, its value is mixed into
2117	  the entropy pool as well. If neither RDRAND nor RDTSC are
2118	  supported, then entropy is read from the i8254 timer. The
2119	  usable entropy is limited by the kernel being built using
2120	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2121	  minimum of 2MB. As a result, only 10 bits of entropy are
2122	  theoretically possible, but the implementations are further
2123	  limited due to memory layouts.
2124
2125	  If unsure, say Y.
2126
2127# Relocation on x86 needs some additional build support
2128config X86_NEED_RELOCS
2129	def_bool y
2130	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2131	select ARCH_VMLINUX_NEEDS_RELOCS
2132
2133config PHYSICAL_ALIGN
2134	hex "Alignment value to which kernel should be aligned"
2135	default "0x200000"
2136	range 0x2000 0x1000000 if X86_32
2137	range 0x200000 0x1000000 if X86_64
2138	help
2139	  This value puts the alignment restrictions on physical address
2140	  where kernel is loaded and run from. Kernel is compiled for an
2141	  address which meets above alignment restriction.
2142
2143	  If bootloader loads the kernel at a non-aligned address and
2144	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2145	  address aligned to above value and run from there.
2146
2147	  If bootloader loads the kernel at a non-aligned address and
2148	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2149	  load address and decompress itself to the address it has been
2150	  compiled for and run from there. The address for which kernel is
2151	  compiled already meets above alignment restrictions. Hence the
2152	  end result is that kernel runs from a physical address meeting
2153	  above alignment restrictions.
2154
2155	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2156	  this value must be a multiple of 0x200000.
2157
2158	  Don't change this unless you know what you are doing.
2159
2160config RANDOMIZE_MEMORY
2161	bool "Randomize the kernel memory sections"
2162	depends on X86_64
2163	depends on RANDOMIZE_BASE
2164	default RANDOMIZE_BASE
2165	help
2166	  Randomizes the base virtual address of kernel memory sections
2167	  (physical memory mapping, vmalloc & vmemmap). This security feature
2168	  makes exploits relying on predictable memory locations less reliable.
2169
2170	  The order of allocations remains unchanged. Entropy is generated in
2171	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2172	  configuration have in average 30,000 different possible virtual
2173	  addresses for each memory section.
2174
2175	  If unsure, say Y.
2176
2177config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2178	hex "Physical memory mapping padding" if EXPERT
2179	depends on RANDOMIZE_MEMORY
2180	default "0xa" if MEMORY_HOTPLUG
2181	default "0x0"
2182	range 0x1 0x40 if MEMORY_HOTPLUG
2183	range 0x0 0x40
2184	help
2185	  Define the padding in terabytes added to the existing physical
2186	  memory size during kernel memory randomization. It is useful
2187	  for memory hotplug support but reduces the entropy available for
2188	  address randomization.
2189
2190	  If unsure, leave at the default value.
2191
2192config ADDRESS_MASKING
2193	bool "Linear Address Masking support"
2194	depends on X86_64
2195	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2196	help
2197	  Linear Address Masking (LAM) modifies the checking that is applied
2198	  to 64-bit linear addresses, allowing software to use of the
2199	  untranslated address bits for metadata.
2200
2201	  The capability can be used for efficient address sanitizers (ASAN)
2202	  implementation and for optimizations in JITs.
2203
2204config HOTPLUG_CPU
2205	def_bool y
2206	depends on SMP
2207
2208config COMPAT_VDSO
2209	def_bool n
2210	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2211	depends on COMPAT_32
2212	help
2213	  Certain buggy versions of glibc will crash if they are
2214	  presented with a 32-bit vDSO that is not mapped at the address
2215	  indicated in its segment table.
2216
2217	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2218	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2219	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2220	  the only released version with the bug, but OpenSUSE 9
2221	  contains a buggy "glibc 2.3.2".
2222
2223	  The symptom of the bug is that everything crashes on startup, saying:
2224	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2225
2226	  Saying Y here changes the default value of the vdso32 boot
2227	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2228	  This works around the glibc bug but hurts performance.
2229
2230	  If unsure, say N: if you are compiling your own kernel, you
2231	  are unlikely to be using a buggy version of glibc.
2232
2233choice
2234	prompt "vsyscall table for legacy applications"
2235	depends on X86_64
2236	default LEGACY_VSYSCALL_XONLY
2237	help
2238	  Legacy user code that does not know how to find the vDSO expects
2239	  to be able to issue three syscalls by calling fixed addresses in
2240	  kernel space. Since this location is not randomized with ASLR,
2241	  it can be used to assist security vulnerability exploitation.
2242
2243	  This setting can be changed at boot time via the kernel command
2244	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2245	  is deprecated and can only be enabled using the kernel command
2246	  line.
2247
2248	  On a system with recent enough glibc (2.14 or newer) and no
2249	  static binaries, you can say None without a performance penalty
2250	  to improve security.
2251
2252	  If unsure, select "Emulate execution only".
2253
2254	config LEGACY_VSYSCALL_XONLY
2255		bool "Emulate execution only"
2256		help
2257		  The kernel traps and emulates calls into the fixed vsyscall
2258		  address mapping and does not allow reads.  This
2259		  configuration is recommended when userspace might use the
2260		  legacy vsyscall area but support for legacy binary
2261		  instrumentation of legacy code is not needed.  It mitigates
2262		  certain uses of the vsyscall area as an ASLR-bypassing
2263		  buffer.
2264
2265	config LEGACY_VSYSCALL_NONE
2266		bool "None"
2267		help
2268		  There will be no vsyscall mapping at all. This will
2269		  eliminate any risk of ASLR bypass due to the vsyscall
2270		  fixed address mapping. Attempts to use the vsyscalls
2271		  will be reported to dmesg, so that either old or
2272		  malicious userspace programs can be identified.
2273
2274endchoice
2275
2276config CMDLINE_BOOL
2277	bool "Built-in kernel command line"
2278	help
2279	  Allow for specifying boot arguments to the kernel at
2280	  build time.  On some systems (e.g. embedded ones), it is
2281	  necessary or convenient to provide some or all of the
2282	  kernel boot arguments with the kernel itself (that is,
2283	  to not rely on the boot loader to provide them.)
2284
2285	  To compile command line arguments into the kernel,
2286	  set this option to 'Y', then fill in the
2287	  boot arguments in CONFIG_CMDLINE.
2288
2289	  Systems with fully functional boot loaders (i.e. non-embedded)
2290	  should leave this option set to 'N'.
2291
2292config CMDLINE
2293	string "Built-in kernel command string"
2294	depends on CMDLINE_BOOL
2295	default ""
2296	help
2297	  Enter arguments here that should be compiled into the kernel
2298	  image and used at boot time.  If the boot loader provides a
2299	  command line at boot time, it is appended to this string to
2300	  form the full kernel command line, when the system boots.
2301
2302	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2303	  change this behavior.
2304
2305	  In most cases, the command line (whether built-in or provided
2306	  by the boot loader) should specify the device for the root
2307	  file system.
2308
2309config CMDLINE_OVERRIDE
2310	bool "Built-in command line overrides boot loader arguments"
2311	depends on CMDLINE_BOOL && CMDLINE != ""
2312	help
2313	  Set this option to 'Y' to have the kernel ignore the boot loader
2314	  command line, and use ONLY the built-in command line.
2315
2316	  This is used to work around broken boot loaders.  This should
2317	  be set to 'N' under normal conditions.
2318
2319config MODIFY_LDT_SYSCALL
2320	bool "Enable the LDT (local descriptor table)" if EXPERT
2321	default y
2322	help
2323	  Linux can allow user programs to install a per-process x86
2324	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2325	  call.  This is required to run 16-bit or segmented code such as
2326	  DOSEMU or some Wine programs.  It is also used by some very old
2327	  threading libraries.
2328
2329	  Enabling this feature adds a small amount of overhead to
2330	  context switches and increases the low-level kernel attack
2331	  surface.  Disabling it removes the modify_ldt(2) system call.
2332
2333	  Saying 'N' here may make sense for embedded or server kernels.
2334
2335config STRICT_SIGALTSTACK_SIZE
2336	bool "Enforce strict size checking for sigaltstack"
2337	depends on DYNAMIC_SIGFRAME
2338	help
2339	  For historical reasons MINSIGSTKSZ is a constant which became
2340	  already too small with AVX512 support. Add a mechanism to
2341	  enforce strict checking of the sigaltstack size against the
2342	  real size of the FPU frame. This option enables the check
2343	  by default. It can also be controlled via the kernel command
2344	  line option 'strict_sas_size' independent of this config
2345	  switch. Enabling it might break existing applications which
2346	  allocate a too small sigaltstack but 'work' because they
2347	  never get a signal delivered.
2348
2349	  Say 'N' unless you want to really enforce this check.
2350
2351config CFI_AUTO_DEFAULT
2352	bool "Attempt to use FineIBT by default at boot time"
2353	depends on FINEIBT
2354	depends on !RUST || RUSTC_VERSION >= 108800
2355	default y
2356	help
2357	  Attempt to use FineIBT by default at boot time. If enabled,
2358	  this is the same as booting with "cfi=auto". If disabled,
2359	  this is the same as booting with "cfi=kcfi".
2360
2361source "kernel/livepatch/Kconfig"
2362
2363config X86_BUS_LOCK_DETECT
2364	bool "Split Lock Detect and Bus Lock Detect support"
2365	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2366	default y
2367	help
2368	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2369	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2370
2371endmenu
2372
2373config CC_HAS_NAMED_AS
2374	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2375	depends on CC_IS_GCC
2376
2377#
2378# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2379# are incompatible with named address spaces with GCC < 13.3
2380# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2381#
2382
2383config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2384	def_bool y
2385	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2386	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2387
2388config USE_X86_SEG_SUPPORT
2389	def_bool CC_HAS_NAMED_AS
2390	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2391
2392config CC_HAS_SLS
2393	def_bool $(cc-option,-mharden-sls=all)
2394
2395config CC_HAS_RETURN_THUNK
2396	def_bool $(cc-option,-mfunction-return=thunk-extern)
2397
2398config CC_HAS_ENTRY_PADDING
2399	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2400
2401config CC_HAS_KCFI_ARITY
2402	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2403	depends on CC_IS_CLANG && !RUST
2404
2405config FUNCTION_PADDING_CFI
2406	int
2407	default 59 if FUNCTION_ALIGNMENT_64B
2408	default 27 if FUNCTION_ALIGNMENT_32B
2409	default 11 if FUNCTION_ALIGNMENT_16B
2410	default  3 if FUNCTION_ALIGNMENT_8B
2411	default  0
2412
2413# Basically: FUNCTION_ALIGNMENT - 5*CFI
2414# except Kconfig can't do arithmetic :/
2415config FUNCTION_PADDING_BYTES
2416	int
2417	default FUNCTION_PADDING_CFI if CFI
2418	default FUNCTION_ALIGNMENT
2419
2420config CALL_PADDING
2421	def_bool n
2422	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2423	select FUNCTION_ALIGNMENT_16B
2424
2425config FINEIBT
2426	def_bool y
2427	depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE
2428	select CALL_PADDING
2429
2430config FINEIBT_BHI
2431	def_bool y
2432	depends on FINEIBT && CC_HAS_KCFI_ARITY
2433
2434config HAVE_CALL_THUNKS
2435	def_bool y
2436	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2437
2438config CALL_THUNKS
2439	def_bool n
2440	select CALL_PADDING
2441
2442config PREFIX_SYMBOLS
2443	def_bool y
2444	depends on CALL_PADDING && !CFI
2445
2446menuconfig CPU_MITIGATIONS
2447	bool "Mitigations for CPU vulnerabilities"
2448	default y
2449	help
2450	  Say Y here to enable options which enable mitigations for hardware
2451	  vulnerabilities (usually related to speculative execution).
2452	  Mitigations can be disabled or restricted to SMT systems at runtime
2453	  via the "mitigations" kernel parameter.
2454
2455	  If you say N, all mitigations will be disabled.  This CANNOT be
2456	  overridden at runtime.
2457
2458	  Say 'Y', unless you really know what you are doing.
2459
2460if CPU_MITIGATIONS
2461
2462config MITIGATION_PAGE_TABLE_ISOLATION
2463	bool "Remove the kernel mapping in user mode"
2464	default y
2465	depends on (X86_64 || X86_PAE)
2466	help
2467	  This feature reduces the number of hardware side channels by
2468	  ensuring that the majority of kernel addresses are not mapped
2469	  into userspace.
2470
2471	  See Documentation/arch/x86/pti.rst for more details.
2472
2473config MITIGATION_RETPOLINE
2474	bool "Avoid speculative indirect branches in kernel"
2475	select OBJTOOL if HAVE_OBJTOOL
2476	default y
2477	help
2478	  Compile kernel with the retpoline compiler options to guard against
2479	  kernel-to-user data leaks by avoiding speculative indirect
2480	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2481	  support for full protection. The kernel may run slower.
2482
2483config MITIGATION_RETHUNK
2484	bool "Enable return-thunks"
2485	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2486	select OBJTOOL if HAVE_OBJTOOL
2487	default y if X86_64
2488	help
2489	  Compile the kernel with the return-thunks compiler option to guard
2490	  against kernel-to-user data leaks by avoiding return speculation.
2491	  Requires a compiler with -mfunction-return=thunk-extern
2492	  support for full protection. The kernel may run slower.
2493
2494config MITIGATION_UNRET_ENTRY
2495	bool "Enable UNRET on kernel entry"
2496	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2497	default y
2498	help
2499	  Compile the kernel with support for the retbleed=unret mitigation.
2500
2501config MITIGATION_CALL_DEPTH_TRACKING
2502	bool "Mitigate RSB underflow with call depth tracking"
2503	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2504	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2505	select CALL_THUNKS
2506	default y
2507	help
2508	  Compile the kernel with call depth tracking to mitigate the Intel
2509	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2510	  by default and needs to be enabled on the kernel command line via the
2511	  retbleed=stuff option. For non-affected systems the overhead of this
2512	  option is marginal as the call depth tracking is using run-time
2513	  generated call thunks in a compiler generated padding area and call
2514	  patching. This increases text size by ~5%. For non affected systems
2515	  this space is unused. On affected SKL systems this results in a
2516	  significant performance gain over the IBRS mitigation.
2517
2518config CALL_THUNKS_DEBUG
2519	bool "Enable call thunks and call depth tracking debugging"
2520	depends on MITIGATION_CALL_DEPTH_TRACKING
2521	select FUNCTION_ALIGNMENT_32B
2522	default n
2523	help
2524	  Enable call/ret counters for imbalance detection and build in
2525	  a noisy dmesg about callthunks generation and call patching for
2526	  trouble shooting. The debug prints need to be enabled on the
2527	  kernel command line with 'debug-callthunks'.
2528	  Only enable this when you are debugging call thunks as this
2529	  creates a noticeable runtime overhead. If unsure say N.
2530
2531config MITIGATION_IBPB_ENTRY
2532	bool "Enable IBPB on kernel entry"
2533	depends on CPU_SUP_AMD && X86_64
2534	default y
2535	help
2536	  Compile the kernel with support for the retbleed=ibpb and
2537	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2538
2539config MITIGATION_IBRS_ENTRY
2540	bool "Enable IBRS on kernel entry"
2541	depends on CPU_SUP_INTEL && X86_64
2542	default y
2543	help
2544	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2545	  This mitigates both spectre_v2 and retbleed at great cost to
2546	  performance.
2547
2548config MITIGATION_SRSO
2549	bool "Mitigate speculative RAS overflow on AMD"
2550	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2551	default y
2552	help
2553	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2554
2555config MITIGATION_SLS
2556	bool "Mitigate Straight-Line-Speculation"
2557	depends on CC_HAS_SLS && X86_64
2558	select OBJTOOL if HAVE_OBJTOOL
2559	default n
2560	help
2561	  Compile the kernel with straight-line-speculation options to guard
2562	  against straight line speculation. The kernel image might be slightly
2563	  larger.
2564
2565config MITIGATION_GDS
2566	bool "Mitigate Gather Data Sampling"
2567	depends on CPU_SUP_INTEL
2568	default y
2569	help
2570	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2571	  vulnerability which allows unprivileged speculative access to data
2572	  which was previously stored in vector registers. The attacker uses gather
2573	  instructions to infer the stale vector register data.
2574
2575config MITIGATION_RFDS
2576	bool "RFDS Mitigation"
2577	depends on CPU_SUP_INTEL
2578	default y
2579	help
2580	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2581	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2582	  allows unprivileged speculative access to stale data previously
2583	  stored in floating point, vector and integer registers.
2584	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2585
2586config MITIGATION_SPECTRE_BHI
2587	bool "Mitigate Spectre-BHB (Branch History Injection)"
2588	depends on CPU_SUP_INTEL
2589	default y
2590	help
2591	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2592	  where the branch history buffer is poisoned to speculatively steer
2593	  indirect branches.
2594	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2595
2596config MITIGATION_MDS
2597	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2598	depends on CPU_SUP_INTEL
2599	default y
2600	help
2601	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2602	  a hardware vulnerability which allows unprivileged speculative access
2603	  to data which is available in various CPU internal buffers.
2604	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2605
2606config MITIGATION_TAA
2607	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2608	depends on CPU_SUP_INTEL
2609	default y
2610	help
2611	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2612	  vulnerability that allows unprivileged speculative access to data
2613	  which is available in various CPU internal buffers by using
2614	  asynchronous aborts within an Intel TSX transactional region.
2615	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2616
2617config MITIGATION_MMIO_STALE_DATA
2618	bool "Mitigate MMIO Stale Data hardware bug"
2619	depends on CPU_SUP_INTEL
2620	default y
2621	help
2622	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2623	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2624	  vulnerabilities that can expose data. The vulnerabilities require the
2625	  attacker to have access to MMIO.
2626	  See also
2627	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2628
2629config MITIGATION_L1TF
2630	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2631	depends on CPU_SUP_INTEL
2632	default y
2633	help
2634	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2635	  hardware vulnerability which allows unprivileged speculative access to data
2636	  available in the Level 1 Data Cache.
2637	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2638
2639config MITIGATION_RETBLEED
2640	bool "Mitigate RETBleed hardware bug"
2641	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2642	default y
2643	help
2644	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2645	  with Return Instructions) vulnerability.  RETBleed is a speculative
2646	  execution attack which takes advantage of microarchitectural behavior
2647	  in many modern microprocessors, similar to Spectre v2. An
2648	  unprivileged attacker can use these flaws to bypass conventional
2649	  memory security restrictions to gain read access to privileged memory
2650	  that would otherwise be inaccessible.
2651
2652config MITIGATION_SPECTRE_V1
2653	bool "Mitigate SPECTRE V1 hardware bug"
2654	default y
2655	help
2656	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2657	  class of side channel attacks that takes advantage of speculative
2658	  execution that bypasses conditional branch instructions used for
2659	  memory access bounds check.
2660	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2661
2662config MITIGATION_SPECTRE_V2
2663	bool "Mitigate SPECTRE V2 hardware bug"
2664	default y
2665	help
2666	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2667	  V2 is a class of side channel attacks that takes advantage of
2668	  indirect branch predictors inside the processor. In Spectre variant 2
2669	  attacks, the attacker can steer speculative indirect branches in the
2670	  victim to gadget code by poisoning the branch target buffer of a CPU
2671	  used for predicting indirect branch addresses.
2672	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2673
2674config MITIGATION_SRBDS
2675	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2676	depends on CPU_SUP_INTEL
2677	default y
2678	help
2679	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2680	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2681	  Sampling (MDS) techniques to infer values returned from special
2682	  register accesses. An unprivileged user can extract values returned
2683	  from RDRAND and RDSEED executed on another core or sibling thread
2684	  using MDS techniques.
2685	  See also
2686	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2687
2688config MITIGATION_SSB
2689	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2690	default y
2691	help
2692	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2693	  hardware security vulnerability and its exploitation takes advantage
2694	  of speculative execution in a similar way to the Meltdown and Spectre
2695	  security vulnerabilities.
2696
2697config MITIGATION_ITS
2698	bool "Enable Indirect Target Selection mitigation"
2699	depends on CPU_SUP_INTEL && X86_64
2700	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2701	select EXECMEM
2702	default y
2703	help
2704	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2705	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2706	  disabled, mitigation cannot be enabled via cmdline.
2707	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2708
2709config MITIGATION_TSA
2710	bool "Mitigate Transient Scheduler Attacks"
2711	depends on CPU_SUP_AMD
2712	default y
2713	help
2714	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2715	  security vulnerability on AMD CPUs which can lead to forwarding of
2716	  invalid info to subsequent instructions and thus can affect their
2717	  timing and thereby cause a leakage.
2718
2719config MITIGATION_VMSCAPE
2720	bool "Mitigate VMSCAPE"
2721	depends on KVM
2722	default y
2723	help
2724	  Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security
2725	  vulnerability on Intel and AMD CPUs that may allow a guest to do
2726	  Spectre v2 style attacks on userspace hypervisor.
2727endif
2728
2729config ARCH_HAS_ADD_PAGES
2730	def_bool y
2731	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2732
2733menu "Power management and ACPI options"
2734
2735config ARCH_HIBERNATION_HEADER
2736	def_bool y
2737	depends on HIBERNATION
2738
2739source "kernel/power/Kconfig"
2740
2741source "drivers/acpi/Kconfig"
2742
2743config X86_APM_BOOT
2744	def_bool y
2745	depends on APM
2746
2747menuconfig APM
2748	tristate "APM (Advanced Power Management) BIOS support"
2749	depends on X86_32 && PM_SLEEP
2750	help
2751	  APM is a BIOS specification for saving power using several different
2752	  techniques. This is mostly useful for battery powered laptops with
2753	  APM compliant BIOSes. If you say Y here, the system time will be
2754	  reset after a RESUME operation, the /proc/apm device will provide
2755	  battery status information, and user-space programs will receive
2756	  notification of APM "events" (e.g. battery status change).
2757
2758	  If you select "Y" here, you can disable actual use of the APM
2759	  BIOS by passing the "apm=off" option to the kernel at boot time.
2760
2761	  Note that the APM support is almost completely disabled for
2762	  machines with more than one CPU.
2763
2764	  In order to use APM, you will need supporting software. For location
2765	  and more information, read <file:Documentation/power/apm-acpi.rst>
2766	  and the Battery Powered Linux mini-HOWTO, available from
2767	  <http://www.tldp.org/docs.html#howto>.
2768
2769	  This driver does not spin down disk drives (see the hdparm(8)
2770	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2771	  VESA-compliant "green" monitors.
2772
2773	  This driver does not support the TI 4000M TravelMate and the ACER
2774	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2775	  desktop machines also don't have compliant BIOSes, and this driver
2776	  may cause those machines to panic during the boot phase.
2777
2778	  Generally, if you don't have a battery in your machine, there isn't
2779	  much point in using this driver and you should say N. If you get
2780	  random kernel OOPSes or reboots that don't seem to be related to
2781	  anything, try disabling/enabling this option (or disabling/enabling
2782	  APM in your BIOS).
2783
2784	  Some other things you should try when experiencing seemingly random,
2785	  "weird" problems:
2786
2787	  1) make sure that you have enough swap space and that it is
2788	  enabled.
2789	  2) pass the "idle=poll" option to the kernel
2790	  3) switch on floating point emulation in the kernel and pass
2791	  the "no387" option to the kernel
2792	  4) pass the "floppy=nodma" option to the kernel
2793	  5) pass the "mem=4M" option to the kernel (thereby disabling
2794	  all but the first 4 MB of RAM)
2795	  6) make sure that the CPU is not over clocked.
2796	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2797	  8) disable the cache from your BIOS settings
2798	  9) install a fan for the video card or exchange video RAM
2799	  10) install a better fan for the CPU
2800	  11) exchange RAM chips
2801	  12) exchange the motherboard.
2802
2803	  To compile this driver as a module, choose M here: the
2804	  module will be called apm.
2805
2806if APM
2807
2808config APM_IGNORE_USER_SUSPEND
2809	bool "Ignore USER SUSPEND"
2810	help
2811	  This option will ignore USER SUSPEND requests. On machines with a
2812	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2813	  series notebooks, it is necessary to say Y because of a BIOS bug.
2814
2815config APM_DO_ENABLE
2816	bool "Enable PM at boot time"
2817	help
2818	  Enable APM features at boot time. From page 36 of the APM BIOS
2819	  specification: "When disabled, the APM BIOS does not automatically
2820	  power manage devices, enter the Standby State, enter the Suspend
2821	  State, or take power saving steps in response to CPU Idle calls."
2822	  This driver will make CPU Idle calls when Linux is idle (unless this
2823	  feature is turned off -- see "Do CPU IDLE calls", below). This
2824	  should always save battery power, but more complicated APM features
2825	  will be dependent on your BIOS implementation. You may need to turn
2826	  this option off if your computer hangs at boot time when using APM
2827	  support, or if it beeps continuously instead of suspending. Turn
2828	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2829	  T400CDT. This is off by default since most machines do fine without
2830	  this feature.
2831
2832config APM_CPU_IDLE
2833	depends on CPU_IDLE
2834	bool "Make CPU Idle calls when idle"
2835	help
2836	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2837	  On some machines, this can activate improved power savings, such as
2838	  a slowed CPU clock rate, when the machine is idle. These idle calls
2839	  are made after the idle loop has run for some length of time (e.g.,
2840	  333 mS). On some machines, this will cause a hang at boot time or
2841	  whenever the CPU becomes idle. (On machines with more than one CPU,
2842	  this option does nothing.)
2843
2844config APM_DISPLAY_BLANK
2845	bool "Enable console blanking using APM"
2846	help
2847	  Enable console blanking using the APM. Some laptops can use this to
2848	  turn off the LCD backlight when the screen blanker of the Linux
2849	  virtual console blanks the screen. Note that this is only used by
2850	  the virtual console screen blanker, and won't turn off the backlight
2851	  when using the X Window system. This also doesn't have anything to
2852	  do with your VESA-compliant power-saving monitor. Further, this
2853	  option doesn't work for all laptops -- it might not turn off your
2854	  backlight at all, or it might print a lot of errors to the console,
2855	  especially if you are using gpm.
2856
2857config APM_ALLOW_INTS
2858	bool "Allow interrupts during APM BIOS calls"
2859	help
2860	  Normally we disable external interrupts while we are making calls to
2861	  the APM BIOS as a measure to lessen the effects of a badly behaving
2862	  BIOS implementation.  The BIOS should reenable interrupts if it
2863	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2864	  many of the newer IBM Thinkpads.  If you experience hangs when you
2865	  suspend, try setting this to Y.  Otherwise, say N.
2866
2867endif # APM
2868
2869source "drivers/cpufreq/Kconfig"
2870
2871source "drivers/cpuidle/Kconfig"
2872
2873source "drivers/idle/Kconfig"
2874
2875endmenu
2876
2877menu "Bus options (PCI etc.)"
2878
2879choice
2880	prompt "PCI access mode"
2881	depends on X86_32 && PCI
2882	default PCI_GOANY
2883	help
2884	  On PCI systems, the BIOS can be used to detect the PCI devices and
2885	  determine their configuration. However, some old PCI motherboards
2886	  have BIOS bugs and may crash if this is done. Also, some embedded
2887	  PCI-based systems don't have any BIOS at all. Linux can also try to
2888	  detect the PCI hardware directly without using the BIOS.
2889
2890	  With this option, you can specify how Linux should detect the
2891	  PCI devices. If you choose "BIOS", the BIOS will be used,
2892	  if you choose "Direct", the BIOS won't be used, and if you
2893	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2894	  If you choose "Any", the kernel will try MMCONFIG, then the
2895	  direct access method and falls back to the BIOS if that doesn't
2896	  work. If unsure, go with the default, which is "Any".
2897
2898config PCI_GOBIOS
2899	bool "BIOS"
2900
2901config PCI_GOMMCONFIG
2902	bool "MMConfig"
2903
2904config PCI_GODIRECT
2905	bool "Direct"
2906
2907config PCI_GOOLPC
2908	bool "OLPC XO-1"
2909	depends on OLPC
2910
2911config PCI_GOANY
2912	bool "Any"
2913
2914endchoice
2915
2916config PCI_BIOS
2917	def_bool y
2918	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2919
2920# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2921config PCI_DIRECT
2922	def_bool y
2923	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2924
2925config PCI_MMCONFIG
2926	bool "Support mmconfig PCI config space access" if X86_64
2927	default y
2928	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2929	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2930	help
2931	  Add support for accessing the PCI configuration space as a memory
2932	  mapped area. It is the recommended method if the system supports
2933	  this (it must have PCI Express and ACPI for it to be available).
2934
2935	  In the unlikely case that enabling this configuration option causes
2936	  problems, the mechanism can be switched off with the 'pci=nommconf'
2937	  command line parameter.
2938
2939	  Say N only if you are sure that your platform does not support this
2940	  access method or you have problems caused by it.
2941
2942	  Say Y otherwise.
2943
2944config PCI_OLPC
2945	def_bool y
2946	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2947
2948config PCI_XEN
2949	def_bool y
2950	depends on PCI && XEN
2951
2952config MMCONF_FAM10H
2953	def_bool y
2954	depends on X86_64 && PCI_MMCONFIG && ACPI
2955
2956config PCI_CNB20LE_QUIRK
2957	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2958	depends on X86_32 && PCI
2959	help
2960	  Read the PCI windows out of the CNB20LE host bridge. This allows
2961	  PCI hotplug to work on systems with the CNB20LE chipset which do
2962	  not have ACPI.
2963
2964	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2965	  most probably only for Pentium III.
2966
2967	  To find out if you have such a chipset, search for a PCI device with
2968	  1166:0009 PCI IDs, for example by executing
2969		lspci -nn | grep '1166:0009'
2970	  The code is inactive if there is none.
2971
2972	  There's no public spec for this chipset, and this functionality
2973	  is known to be incomplete.
2974
2975	  You should say N unless you know you need this.
2976
2977config ISA_BUS
2978	bool "ISA bus support on modern systems" if EXPERT
2979	help
2980	  Expose ISA bus device drivers and options available for selection and
2981	  configuration. Enable this option if your target machine has an ISA
2982	  bus. ISA is an older system, displaced by PCI and newer bus
2983	  architectures -- if your target machine is modern, it probably does
2984	  not have an ISA bus.
2985
2986	  If unsure, say N.
2987
2988# x86_64 have no ISA slots, but can have ISA-style DMA.
2989config ISA_DMA_API
2990	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2991	default y
2992	help
2993	  Enables ISA-style DMA support for devices requiring such controllers.
2994	  If unsure, say Y.
2995
2996if X86_32
2997
2998config ISA
2999	bool "ISA support"
3000	help
3001	  Find out whether you have ISA slots on your motherboard.  ISA is the
3002	  name of a bus system, i.e. the way the CPU talks to the other stuff
3003	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
3004	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
3005	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
3006
3007config SCx200
3008	tristate "NatSemi SCx200 support"
3009	help
3010	  This provides basic support for National Semiconductor's
3011	  (now AMD's) Geode processors.  The driver probes for the
3012	  PCI-IDs of several on-chip devices, so its a good dependency
3013	  for other scx200_* drivers.
3014
3015	  If compiled as a module, the driver is named scx200.
3016
3017config SCx200HR_TIMER
3018	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
3019	depends on SCx200
3020	default y
3021	help
3022	  This driver provides a clocksource built upon the on-chip
3023	  27MHz high-resolution timer.  Its also a workaround for
3024	  NSC Geode SC-1100's buggy TSC, which loses time when the
3025	  processor goes idle (as is done by the scheduler).  The
3026	  other workaround is idle=poll boot option.
3027
3028config OLPC
3029	bool "One Laptop Per Child support"
3030	depends on !X86_PAE
3031	select GPIOLIB
3032	select OF
3033	select OF_PROMTREE
3034	select IRQ_DOMAIN
3035	select OLPC_EC
3036	help
3037	  Add support for detecting the unique features of the OLPC
3038	  XO hardware.
3039
3040config OLPC_XO1_PM
3041	bool "OLPC XO-1 Power Management"
3042	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3043	help
3044	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3045
3046config OLPC_XO1_RTC
3047	bool "OLPC XO-1 Real Time Clock"
3048	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3049	help
3050	  Add support for the XO-1 real time clock, which can be used as a
3051	  programmable wakeup source.
3052
3053config OLPC_XO1_SCI
3054	bool "OLPC XO-1 SCI extras"
3055	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3056	depends on INPUT=y
3057	select POWER_SUPPLY
3058	help
3059	  Add support for SCI-based features of the OLPC XO-1 laptop:
3060	   - EC-driven system wakeups
3061	   - Power button
3062	   - Ebook switch
3063	   - Lid switch
3064	   - AC adapter status updates
3065	   - Battery status updates
3066
3067config OLPC_XO15_SCI
3068	bool "OLPC XO-1.5 SCI extras"
3069	depends on OLPC && ACPI
3070	select POWER_SUPPLY
3071	help
3072	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3073	   - EC-driven system wakeups
3074	   - AC adapter status updates
3075	   - Battery status updates
3076
3077config GEODE_COMMON
3078	bool
3079
3080config ALIX
3081	bool "PCEngines ALIX System Support (LED setup)"
3082	select GPIOLIB
3083	select GEODE_COMMON
3084	help
3085	  This option enables system support for the PCEngines ALIX.
3086	  At present this just sets up LEDs for GPIO control on
3087	  ALIX2/3/6 boards.  However, other system specific setup should
3088	  get added here.
3089
3090	  Note: You must still enable the drivers for GPIO and LED support
3091	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3092
3093	  Note: You have to set alix.force=1 for boards with Award BIOS.
3094
3095config NET5501
3096	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3097	select GPIOLIB
3098	select GEODE_COMMON
3099	help
3100	  This option enables system support for the Soekris Engineering net5501.
3101
3102config GEOS
3103	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3104	select GPIOLIB
3105	select GEODE_COMMON
3106	depends on DMI
3107	help
3108	  This option enables system support for the Traverse Technologies GEOS.
3109
3110config TS5500
3111	bool "Technologic Systems TS-5500 platform support"
3112	depends on MELAN
3113	select CHECK_SIGNATURE
3114	select NEW_LEDS
3115	select LEDS_CLASS
3116	help
3117	  This option enables system support for the Technologic Systems TS-5500.
3118
3119endif # X86_32
3120
3121config AMD_NB
3122	def_bool y
3123	depends on AMD_NODE
3124
3125config AMD_NODE
3126	def_bool y
3127	depends on CPU_SUP_AMD && PCI
3128
3129endmenu
3130
3131menu "Binary Emulations"
3132
3133config IA32_EMULATION
3134	bool "IA32 Emulation"
3135	depends on X86_64
3136	select ARCH_WANT_OLD_COMPAT_IPC
3137	select BINFMT_ELF
3138	select COMPAT_OLD_SIGACTION
3139	help
3140	  Include code to run legacy 32-bit programs under a
3141	  64-bit kernel. You should likely turn this on, unless you're
3142	  100% sure that you don't have any 32-bit programs left.
3143
3144config IA32_EMULATION_DEFAULT_DISABLED
3145	bool "IA32 emulation disabled by default"
3146	default n
3147	depends on IA32_EMULATION
3148	help
3149	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3150	  processes and access to 32-bit syscalls. If unsure, leave it to its
3151	  default value.
3152
3153config X86_X32_ABI
3154	bool "x32 ABI for 64-bit mode"
3155	depends on X86_64
3156	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3157	# compressed debug sections to x86_x32 properly:
3158	# https://github.com/ClangBuiltLinux/linux/issues/514
3159	# https://github.com/ClangBuiltLinux/linux/issues/1141
3160	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3161	help
3162	  Include code to run binaries for the x32 native 32-bit ABI
3163	  for 64-bit processors.  An x32 process gets access to the
3164	  full 64-bit register file and wide data path while leaving
3165	  pointers at 32 bits for smaller memory footprint.
3166
3167config COMPAT_32
3168	def_bool y
3169	depends on IA32_EMULATION || X86_32
3170	select HAVE_UID16
3171	select OLD_SIGSUSPEND3
3172
3173config COMPAT
3174	def_bool y
3175	depends on IA32_EMULATION || X86_X32_ABI
3176
3177config COMPAT_FOR_U64_ALIGNMENT
3178	def_bool y
3179	depends on COMPAT
3180
3181endmenu
3182
3183config HAVE_ATOMIC_IOMAP
3184	def_bool y
3185	depends on X86_32
3186
3187source "arch/x86/kvm/Kconfig"
3188
3189source "arch/x86/Kconfig.cpufeatures"
3190
3191source "arch/x86/Kconfig.assembler"
3192