xref: /linux/arch/x86/Kconfig (revision bf76f23aa1c178e9115eba17f699fa726aed669b)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select GENERIC_VDSO_32
18	select HAVE_DEBUG_STACKOVERFLOW
19	select KMAP_LOCAL
20	select MODULES_USE_ELF_REL
21	select OLD_SIGACTION
22	select ARCH_SPLIT_ARG64
23
24config X86_64
25	def_bool y
26	depends on 64BIT
27	# Options that are inherently 64-bit kernel only:
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_HAS_PTDUMP
30	select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
31	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
32	select ARCH_SUPPORTS_PER_VMA_LOCK
33	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
34	select HAVE_ARCH_SOFT_DIRTY
35	select MODULES_USE_ELF_RELA
36	select NEED_DMA_MAP_STATE
37	select SWIOTLB
38	select ARCH_HAS_ELFCORE_COMPAT
39	select ZONE_DMA32
40	select EXECMEM if DYNAMIC_FTRACE
41	select ACPI_MRRM if ACPI
42
43config FORCE_DYNAMIC_FTRACE
44	def_bool y
45	depends on X86_32
46	depends on FUNCTION_TRACER
47	select DYNAMIC_FTRACE
48	help
49	  We keep the static function tracing (!DYNAMIC_FTRACE) around
50	  in order to test the non static function tracing in the
51	  generic code, as other architectures still use it. But we
52	  only need to keep it around for x86_64. No need to keep it
53	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
54#
55# Arch settings
56#
57# ( Note that options that are marked 'if X86_64' could in principle be
58#   ported to 32-bit as well. )
59#
60config X86
61	def_bool y
62	#
63	# Note: keep this list sorted alphabetically
64	#
65	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
66	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
67	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
68	select ARCH_32BIT_OFF_T			if X86_32
69	select ARCH_CLOCKSOURCE_INIT
70	select ARCH_CONFIGURES_CPU_MITIGATIONS
71	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
72	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
73	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
74	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
75	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
76	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
77	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
78	select ARCH_HAS_CPU_ATTACK_VECTORS	if CPU_MITIGATIONS
79	select ARCH_HAS_CACHE_LINE_SIZE
80	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
81	select ARCH_HAS_CPU_FINALIZE_INIT
82	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
83	select ARCH_HAS_CURRENT_STACK_POINTER
84	select ARCH_HAS_DEBUG_VIRTUAL
85	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
86	select ARCH_HAS_DEVMEM_IS_ALLOWED
87	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
88	select ARCH_HAS_EARLY_DEBUG		if KGDB
89	select ARCH_HAS_ELF_RANDOMIZE
90	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
91	select ARCH_HAS_FAST_MULTIPLIER
92	select ARCH_HAS_FORTIFY_SOURCE
93	select ARCH_HAS_GCOV_PROFILE_ALL
94	select ARCH_HAS_KCOV			if X86_64
95	select ARCH_HAS_KERNEL_FPU_SUPPORT
96	select ARCH_HAS_MEM_ENCRYPT
97	select ARCH_HAS_MEMBARRIER_SYNC_CORE
98	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
99	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
100	select ARCH_HAS_PMEM_API		if X86_64
101	select ARCH_HAS_PREEMPT_LAZY
102	select ARCH_HAS_PTE_DEVMAP		if X86_64
103	select ARCH_HAS_PTE_SPECIAL
104	select ARCH_HAS_HW_PTE_YOUNG
105	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
106	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
107	select ARCH_HAS_COPY_MC			if X86_64
108	select ARCH_HAS_SET_MEMORY
109	select ARCH_HAS_SET_DIRECT_MAP
110	select ARCH_HAS_STRICT_KERNEL_RWX
111	select ARCH_HAS_STRICT_MODULE_RWX
112	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
113	select ARCH_HAS_SYSCALL_WRAPPER
114	select ARCH_HAS_UBSAN
115	select ARCH_HAS_DEBUG_WX
116	select ARCH_HAS_ZONE_DMA_SET if EXPERT
117	select ARCH_HAVE_NMI_SAFE_CMPXCHG
118	select ARCH_HAVE_EXTRA_ELF_NOTES
119	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
120	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
121	select ARCH_MIGHT_HAVE_PC_PARPORT
122	select ARCH_MIGHT_HAVE_PC_SERIO
123	select ARCH_STACKWALK
124	select ARCH_SUPPORTS_ACPI
125	select ARCH_SUPPORTS_ATOMIC_RMW
126	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
127	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
128	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
129	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
130	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
131	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
132	select ARCH_SUPPORTS_LTO_CLANG
133	select ARCH_SUPPORTS_LTO_CLANG_THIN
134	select ARCH_SUPPORTS_RT
135	select ARCH_SUPPORTS_AUTOFDO_CLANG
136	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
137	select ARCH_USE_BUILTIN_BSWAP
138	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
139	select ARCH_USE_MEMTEST
140	select ARCH_USE_QUEUED_RWLOCKS
141	select ARCH_USE_QUEUED_SPINLOCKS
142	select ARCH_USE_SYM_ANNOTATIONS
143	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
144	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
145	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
146	select ARCH_WANTS_NO_INSTR
147	select ARCH_WANT_GENERAL_HUGETLB
148	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
149	select ARCH_WANT_LD_ORPHAN_WARN
150	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
151	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
152	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
153	select ARCH_WANTS_THP_SWAP		if X86_64
154	select ARCH_HAS_PARANOID_L1D_FLUSH
155	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
156	select BUILDTIME_TABLE_SORT
157	select CLKEVT_I8253
158	select CLOCKSOURCE_WATCHDOG
159	# Word-size accesses may read uninitialized data past the trailing \0
160	# in strings and cause false KMSAN reports.
161	select DCACHE_WORD_ACCESS		if !KMSAN
162	select DYNAMIC_SIGFRAME
163	select EDAC_ATOMIC_SCRUB
164	select EDAC_SUPPORT
165	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
166	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
167	select GENERIC_CLOCKEVENTS_MIN_ADJUST
168	select GENERIC_CMOS_UPDATE
169	select GENERIC_CPU_AUTOPROBE
170	select GENERIC_CPU_DEVICES
171	select GENERIC_CPU_VULNERABILITIES
172	select GENERIC_EARLY_IOREMAP
173	select GENERIC_ENTRY
174	select GENERIC_IOMAP
175	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
176	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
177	select GENERIC_IRQ_MIGRATION		if SMP
178	select GENERIC_IRQ_PROBE
179	select GENERIC_IRQ_RESERVATION_MODE
180	select GENERIC_IRQ_SHOW
181	select GENERIC_PENDING_IRQ		if SMP
182	select GENERIC_SMP_IDLE_THREAD
183	select GENERIC_TIME_VSYSCALL
184	select GENERIC_GETTIMEOFDAY
185	select GENERIC_VDSO_DATA_STORE
186	select GENERIC_VDSO_TIME_NS
187	select GENERIC_VDSO_OVERFLOW_PROTECT
188	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
189	select HARDIRQS_SW_RESEND
190	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
191	select HAS_IOPORT
192	select HAVE_ACPI_APEI			if ACPI
193	select HAVE_ACPI_APEI_NMI		if ACPI
194	select HAVE_ALIGNED_STRUCT_PAGE
195	select HAVE_ARCH_AUDITSYSCALL
196	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
197	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
198	select HAVE_ARCH_JUMP_LABEL
199	select HAVE_ARCH_JUMP_LABEL_RELATIVE
200	select HAVE_ARCH_KASAN			if X86_64
201	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
202	select HAVE_ARCH_KFENCE
203	select HAVE_ARCH_KMSAN			if X86_64
204	select HAVE_ARCH_KGDB
205	select HAVE_ARCH_KSTACK_ERASE
206	select HAVE_ARCH_MMAP_RND_BITS		if MMU
207	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
208	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
209	select HAVE_ARCH_PREL32_RELOCATIONS
210	select HAVE_ARCH_SECCOMP_FILTER
211	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
212	select HAVE_ARCH_TRACEHOOK
213	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
214	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
215	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
216	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
217	select HAVE_ARCH_VMAP_STACK		if X86_64
218	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
219	select HAVE_ARCH_WITHIN_STACK_FRAMES
220	select HAVE_ASM_MODVERSIONS
221	select HAVE_CMPXCHG_DOUBLE
222	select HAVE_CMPXCHG_LOCAL
223	select HAVE_CONTEXT_TRACKING_USER		if X86_64
224	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
225	select HAVE_C_RECORDMCOUNT
226	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
227	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
228	select HAVE_BUILDTIME_MCOUNT_SORT
229	select HAVE_DEBUG_KMEMLEAK
230	select HAVE_DMA_CONTIGUOUS
231	select HAVE_DYNAMIC_FTRACE
232	select HAVE_DYNAMIC_FTRACE_WITH_REGS
233	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
234	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
235	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
236	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
237	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
238	select HAVE_EBPF_JIT
239	select HAVE_EFFICIENT_UNALIGNED_ACCESS
240	select HAVE_EISA			if X86_32
241	select HAVE_EXIT_THREAD
242	select HAVE_GUP_FAST
243	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
244	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
245	select HAVE_FTRACE_MCOUNT_RECORD
246	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
247	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
248	select HAVE_FUNCTION_TRACER
249	select HAVE_GCC_PLUGINS
250	select HAVE_HW_BREAKPOINT
251	select HAVE_IOREMAP_PROT
252	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
253	select HAVE_IRQ_TIME_ACCOUNTING
254	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
255	select HAVE_KERNEL_BZIP2
256	select HAVE_KERNEL_GZIP
257	select HAVE_KERNEL_LZ4
258	select HAVE_KERNEL_LZMA
259	select HAVE_KERNEL_LZO
260	select HAVE_KERNEL_XZ
261	select HAVE_KERNEL_ZSTD
262	select HAVE_KPROBES
263	select HAVE_KPROBES_ON_FTRACE
264	select HAVE_FUNCTION_ERROR_INJECTION
265	select HAVE_KRETPROBES
266	select HAVE_RETHOOK
267	select HAVE_LIVEPATCH			if X86_64
268	select HAVE_MIXED_BREAKPOINTS_REGS
269	select HAVE_MOD_ARCH_SPECIFIC
270	select HAVE_MOVE_PMD
271	select HAVE_MOVE_PUD
272	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
273	select HAVE_NMI
274	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
275	select HAVE_OBJTOOL			if X86_64
276	select HAVE_OPTPROBES
277	select HAVE_PAGE_SIZE_4KB
278	select HAVE_PCSPKR_PLATFORM
279	select HAVE_PERF_EVENTS
280	select HAVE_PERF_EVENTS_NMI
281	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
282	select HAVE_PCI
283	select HAVE_PERF_REGS
284	select HAVE_PERF_USER_STACK_DUMP
285	select MMU_GATHER_RCU_TABLE_FREE
286	select MMU_GATHER_MERGE_VMAS
287	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
288	select HAVE_REGS_AND_STACK_ACCESS_API
289	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
290	select HAVE_FUNCTION_ARG_ACCESS_API
291	select HAVE_SETUP_PER_CPU_AREA
292	select HAVE_SOFTIRQ_ON_OWN_STACK
293	select HAVE_STACKPROTECTOR
294	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
295	select HAVE_STATIC_CALL
296	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
297	select HAVE_PREEMPT_DYNAMIC_CALL
298	select HAVE_RSEQ
299	select HAVE_RUST			if X86_64
300	select HAVE_SYSCALL_TRACEPOINTS
301	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
302	select HAVE_UNSTABLE_SCHED_CLOCK
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_PT_RECLAIM		if X86_64
334
335config INSTRUCTION_DECODER
336	def_bool y
337	depends on KPROBES || PERF_EVENTS || UPROBES
338
339config OUTPUT_FORMAT
340	string
341	default "elf32-i386" if X86_32
342	default "elf64-x86-64" if X86_64
343
344config LOCKDEP_SUPPORT
345	def_bool y
346
347config STACKTRACE_SUPPORT
348	def_bool y
349
350config MMU
351	def_bool y
352
353config ARCH_MMAP_RND_BITS_MIN
354	default 28 if 64BIT
355	default 8
356
357config ARCH_MMAP_RND_BITS_MAX
358	default 32 if 64BIT
359	default 16
360
361config ARCH_MMAP_RND_COMPAT_BITS_MIN
362	default 8
363
364config ARCH_MMAP_RND_COMPAT_BITS_MAX
365	default 16
366
367config SBUS
368	bool
369
370config GENERIC_ISA_DMA
371	def_bool y
372	depends on ISA_DMA_API
373
374config GENERIC_CSUM
375	bool
376	default y if KMSAN || KASAN
377
378config GENERIC_BUG
379	def_bool y
380	depends on BUG
381	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
382
383config GENERIC_BUG_RELATIVE_POINTERS
384	bool
385
386config ARCH_MAY_HAVE_PC_FDC
387	def_bool y
388	depends on ISA_DMA_API
389
390config GENERIC_CALIBRATE_DELAY
391	def_bool y
392
393config ARCH_HAS_CPU_RELAX
394	def_bool y
395
396config ARCH_HIBERNATION_POSSIBLE
397	def_bool y
398
399config ARCH_SUSPEND_POSSIBLE
400	def_bool y
401
402config AUDIT_ARCH
403	def_bool y if X86_64
404
405config KASAN_SHADOW_OFFSET
406	hex
407	depends on KASAN
408	default 0xdffffc0000000000
409
410config HAVE_INTEL_TXT
411	def_bool y
412	depends on INTEL_IOMMU && ACPI
413
414config X86_64_SMP
415	def_bool y
416	depends on X86_64 && SMP
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 X86_POSTED_MSI
488	bool "Enable MSI and MSI-x delivery by posted interrupts"
489	depends on X86_64 && IRQ_REMAP
490	help
491	  This enables MSIs that are under interrupt remapping to be delivered as
492	  posted interrupts to the host kernel. Interrupt throughput can
493	  potentially be improved by coalescing CPU notifications during high
494	  frequency bursts.
495
496	  If you don't know what to do here, say N.
497
498config X86_MPPARSE
499	bool "Enable MPS table" if ACPI
500	default y
501	depends on X86_LOCAL_APIC
502	help
503	  For old smp systems that do not have proper acpi support. Newer systems
504	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
505
506config X86_CPU_RESCTRL
507	bool "x86 CPU resource control support"
508	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
509	depends on MISC_FILESYSTEMS
510	select ARCH_HAS_CPU_RESCTRL
511	select RESCTRL_FS
512	select RESCTRL_FS_PSEUDO_LOCK
513	help
514	  Enable x86 CPU resource control support.
515
516	  Provide support for the allocation and monitoring of system resources
517	  usage by the CPU.
518
519	  Intel calls this Intel Resource Director Technology
520	  (Intel(R) RDT). More information about RDT can be found in the
521	  Intel x86 Architecture Software Developer Manual.
522
523	  AMD calls this AMD Platform Quality of Service (AMD QoS).
524	  More information about AMD QoS can be found in the AMD64 Technology
525	  Platform Quality of Service Extensions manual.
526
527	  Say N if unsure.
528
529config X86_FRED
530	bool "Flexible Return and Event Delivery"
531	depends on X86_64
532	help
533	  When enabled, try to use Flexible Return and Event Delivery
534	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
535	  ring transitions and exception/interrupt handling if the
536	  system supports it.
537
538config X86_EXTENDED_PLATFORM
539	bool "Support for extended (non-PC) x86 platforms"
540	default y
541	help
542	  If you disable this option then the kernel will only support
543	  standard PC platforms. (which covers the vast majority of
544	  systems out there.)
545
546	  If you enable this option then you'll be able to select support
547	  for the following non-PC x86 platforms, depending on the value of
548	  CONFIG_64BIT.
549
550	  32-bit platforms (CONFIG_64BIT=n):
551		Goldfish (mostly Android emulator)
552		Intel CE media processor (CE4100) SoC
553		Intel Quark
554		RDC R-321x SoC
555
556	  64-bit platforms (CONFIG_64BIT=y):
557		Numascale NumaChip
558		ScaleMP vSMP
559		SGI Ultraviolet
560		Merrifield/Moorefield MID devices
561		Goldfish (mostly Android emulator)
562
563	  If you have one of these systems, or if you want to build a
564	  generic distribution kernel, say Y here - otherwise say N.
565
566# This is an alphabetically sorted list of 64 bit extended platforms
567# Please maintain the alphabetic order if and when there are additions
568config X86_NUMACHIP
569	bool "Numascale NumaChip"
570	depends on X86_64
571	depends on X86_EXTENDED_PLATFORM
572	depends on NUMA
573	depends on SMP
574	depends on X86_X2APIC
575	depends on PCI_MMCONFIG
576	help
577	  Adds support for Numascale NumaChip large-SMP systems. Needed to
578	  enable more than ~168 cores.
579	  If you don't have one of these, you should say N here.
580
581config X86_VSMP
582	bool "ScaleMP vSMP"
583	select HYPERVISOR_GUEST
584	select PARAVIRT
585	depends on X86_64 && PCI
586	depends on X86_EXTENDED_PLATFORM
587	depends on SMP
588	help
589	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
590	  supposed to run on these EM64T-based machines.  Only choose this option
591	  if you have one of these machines.
592
593config X86_UV
594	bool "SGI Ultraviolet"
595	depends on X86_64
596	depends on X86_EXTENDED_PLATFORM
597	depends on NUMA
598	depends on EFI
599	depends on KEXEC_CORE
600	depends on X86_X2APIC
601	depends on PCI
602	help
603	  This option is needed in order to support SGI Ultraviolet systems.
604	  If you don't have one of these, you should say N here.
605
606config X86_INTEL_MID
607	bool "Intel Z34xx/Z35xx MID platform support"
608	depends on X86_EXTENDED_PLATFORM
609	depends on X86_PLATFORM_DEVICES
610	depends on PCI
611	depends on X86_64 || (EXPERT && PCI_GOANY)
612	depends on X86_IO_APIC
613	select I2C
614	select DW_APB_TIMER
615	select INTEL_SCU_PCI
616	help
617	  Select to build a kernel capable of supporting 64-bit Intel MID
618	  (Mobile Internet Device) platform systems which do not have
619	  the PCI legacy interfaces.
620
621	  The only supported devices are the 22nm Merrified (Z34xx)
622	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
623	  a small number of Android devices such as the Asus Zenfone 2,
624	  Asus FonePad 8 and Dell Venue 7.
625
626	  If you are building for a PC class system or non-MID tablet
627	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
628
629	  Intel MID platforms are based on an Intel processor and chipset which
630	  consume less power than most of the x86 derivatives.
631
632config X86_GOLDFISH
633	bool "Goldfish (Virtual Platform)"
634	depends on X86_EXTENDED_PLATFORM
635	help
636	  Enable support for the Goldfish virtual platform used primarily
637	  for Android development. Unless you are building for the Android
638	  Goldfish emulator say N here.
639
640# Following is an alphabetically sorted list of 32 bit extended platforms
641# Please maintain the alphabetic order if and when there are additions
642
643config X86_INTEL_CE
644	bool "CE4100 TV platform"
645	depends on PCI
646	depends on PCI_GODIRECT
647	depends on X86_IO_APIC
648	depends on X86_32
649	depends on X86_EXTENDED_PLATFORM
650	select X86_REBOOTFIXUPS
651	select OF
652	select OF_EARLY_FLATTREE
653	help
654	  Select for the Intel CE media processor (CE4100) SOC.
655	  This option compiles in support for the CE4100 SOC for settop
656	  boxes and media devices.
657
658config X86_INTEL_QUARK
659	bool "Intel Quark platform support"
660	depends on X86_32
661	depends on X86_EXTENDED_PLATFORM
662	depends on X86_PLATFORM_DEVICES
663	depends on X86_TSC
664	depends on PCI
665	depends on PCI_GOANY
666	depends on X86_IO_APIC
667	select IOSF_MBI
668	select INTEL_IMR
669	select COMMON_CLK
670	help
671	  Select to include support for Quark X1000 SoC.
672	  Say Y here if you have a Quark based system such as the Arduino
673	  compatible Intel Galileo.
674
675config X86_RDC321X
676	bool "RDC R-321x SoC"
677	depends on X86_32
678	depends on X86_EXTENDED_PLATFORM
679	select M486
680	select X86_REBOOTFIXUPS
681	help
682	  This option is needed for RDC R-321x system-on-chip, also known
683	  as R-8610-(G).
684	  If you don't have one of these chips, you should say N here.
685
686config X86_INTEL_LPSS
687	bool "Intel Low Power Subsystem Support"
688	depends on X86 && ACPI && PCI
689	select COMMON_CLK
690	select PINCTRL
691	select IOSF_MBI
692	help
693	  Select to build support for Intel Low Power Subsystem such as
694	  found on Intel Lynxpoint PCH. Selecting this option enables
695	  things like clock tree (common clock framework) and pincontrol
696	  which are needed by the LPSS peripheral drivers.
697
698config X86_AMD_PLATFORM_DEVICE
699	bool "AMD ACPI2Platform devices support"
700	depends on ACPI
701	select COMMON_CLK
702	select PINCTRL
703	help
704	  Select to interpret AMD specific ACPI device to platform device
705	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
706	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
707	  implemented under PINCTRL subsystem.
708
709config IOSF_MBI
710	tristate "Intel SoC IOSF Sideband support for SoC platforms"
711	depends on PCI
712	help
713	  This option enables sideband register access support for Intel SoC
714	  platforms. On these platforms the IOSF sideband is used in lieu of
715	  MSR's for some register accesses, mostly but not limited to thermal
716	  and power. Drivers may query the availability of this device to
717	  determine if they need the sideband in order to work on these
718	  platforms. The sideband is available on the following SoC products.
719	  This list is not meant to be exclusive.
720	   - BayTrail
721	   - Braswell
722	   - Quark
723
724	  You should say Y if you are running a kernel on one of these SoC's.
725
726config IOSF_MBI_DEBUG
727	bool "Enable IOSF sideband access through debugfs"
728	depends on IOSF_MBI && DEBUG_FS
729	help
730	  Select this option to expose the IOSF sideband access registers (MCR,
731	  MDR, MCRX) through debugfs to write and read register information from
732	  different units on the SoC. This is most useful for obtaining device
733	  state information for debug and analysis. As this is a general access
734	  mechanism, users of this option would have specific knowledge of the
735	  device they want to access.
736
737	  If you don't require the option or are in doubt, say N.
738
739config X86_SUPPORTS_MEMORY_FAILURE
740	def_bool y
741	# MCE code calls memory_failure():
742	depends on X86_MCE
743	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
744	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
745	depends on X86_64 || !SPARSEMEM
746	select ARCH_SUPPORTS_MEMORY_FAILURE
747
748config X86_32_IRIS
749	tristate "Eurobraille/Iris poweroff module"
750	depends on X86_32
751	help
752	  The Iris machines from EuroBraille do not have APM or ACPI support
753	  to shut themselves down properly.  A special I/O sequence is
754	  needed to do so, which is what this module does at
755	  kernel shutdown.
756
757	  This is only for Iris machines from EuroBraille.
758
759	  If unused, say N.
760
761config SCHED_OMIT_FRAME_POINTER
762	def_bool y
763	prompt "Single-depth WCHAN output"
764	depends on X86
765	help
766	  Calculate simpler /proc/<PID>/wchan values. If this option
767	  is disabled then wchan values will recurse back to the
768	  caller function. This provides more accurate wchan values,
769	  at the expense of slightly more scheduling overhead.
770
771	  If in doubt, say "Y".
772
773menuconfig HYPERVISOR_GUEST
774	bool "Linux guest support"
775	help
776	  Say Y here to enable options for running Linux under various hyper-
777	  visors. This option enables basic hypervisor detection and platform
778	  setup.
779
780	  If you say N, all options in this submenu will be skipped and
781	  disabled, and Linux guest support won't be built in.
782
783if HYPERVISOR_GUEST
784
785config PARAVIRT
786	bool "Enable paravirtualization code"
787	depends on HAVE_STATIC_CALL
788	help
789	  This changes the kernel so it can modify itself when it is run
790	  under a hypervisor, potentially improving performance significantly
791	  over full virtualization.  However, when run without a hypervisor
792	  the kernel is theoretically slower and slightly larger.
793
794config PARAVIRT_XXL
795	bool
796	depends on X86_64
797
798config PARAVIRT_DEBUG
799	bool "paravirt-ops debugging"
800	depends on PARAVIRT && DEBUG_KERNEL
801	help
802	  Enable to debug paravirt_ops internals.  Specifically, BUG if
803	  a paravirt_op is missing when it is called.
804
805config PARAVIRT_SPINLOCKS
806	bool "Paravirtualization layer for spinlocks"
807	depends on PARAVIRT && SMP
808	help
809	  Paravirtualized spinlocks allow a pvops backend to replace the
810	  spinlock implementation with something virtualization-friendly
811	  (for example, block the virtual CPU rather than spinning).
812
813	  It has a minimal impact on native kernels and gives a nice performance
814	  benefit on paravirtualized KVM / Xen kernels.
815
816	  If you are unsure how to answer this question, answer Y.
817
818config X86_HV_CALLBACK_VECTOR
819	def_bool n
820
821source "arch/x86/xen/Kconfig"
822
823config KVM_GUEST
824	bool "KVM Guest support (including kvmclock)"
825	depends on PARAVIRT
826	select PARAVIRT_CLOCK
827	select ARCH_CPUIDLE_HALTPOLL
828	select X86_HV_CALLBACK_VECTOR
829	default y
830	help
831	  This option enables various optimizations for running under the KVM
832	  hypervisor. It includes a paravirtualized clock, so that instead
833	  of relying on a PIT (or probably other) emulation by the
834	  underlying device model, the host provides the guest with
835	  timing infrastructure such as time of day, and system time
836
837config ARCH_CPUIDLE_HALTPOLL
838	def_bool n
839	prompt "Disable host haltpoll when loading haltpoll driver"
840	help
841	  If virtualized under KVM, disable host haltpoll.
842
843config PVH
844	bool "Support for running PVH guests"
845	help
846	  This option enables the PVH entry point for guest virtual machines
847	  as specified in the x86/HVM direct boot ABI.
848
849config PARAVIRT_TIME_ACCOUNTING
850	bool "Paravirtual steal time accounting"
851	depends on PARAVIRT
852	help
853	  Select this option to enable fine granularity task steal time
854	  accounting. Time spent executing other tasks in parallel with
855	  the current vCPU is discounted from the vCPU power. To account for
856	  that, there can be a small performance impact.
857
858	  If in doubt, say N here.
859
860config PARAVIRT_CLOCK
861	bool
862
863config JAILHOUSE_GUEST
864	bool "Jailhouse non-root cell support"
865	depends on X86_64 && PCI
866	select X86_PM_TIMER
867	help
868	  This option allows to run Linux as guest in a Jailhouse non-root
869	  cell. You can leave this option disabled if you only want to start
870	  Jailhouse and run Linux afterwards in the root cell.
871
872config ACRN_GUEST
873	bool "ACRN Guest support"
874	depends on X86_64
875	select X86_HV_CALLBACK_VECTOR
876	help
877	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
878	  a flexible, lightweight reference open-source hypervisor, built with
879	  real-time and safety-criticality in mind. It is built for embedded
880	  IOT with small footprint and real-time features. More details can be
881	  found in https://projectacrn.org/.
882
883config INTEL_TDX_GUEST
884	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
885	depends on X86_64 && CPU_SUP_INTEL
886	depends on X86_X2APIC
887	depends on EFI_STUB
888	depends on PARAVIRT
889	select ARCH_HAS_CC_PLATFORM
890	select X86_MEM_ENCRYPT
891	select X86_MCE
892	select UNACCEPTED_MEMORY
893	help
894	  Support running as a guest under Intel TDX.  Without this support,
895	  the guest kernel can not boot or run under TDX.
896	  TDX includes memory encryption and integrity capabilities
897	  which protect the confidentiality and integrity of guest
898	  memory contents and CPU state. TDX guests are protected from
899	  some attacks from the VMM.
900
901endif # HYPERVISOR_GUEST
902
903source "arch/x86/Kconfig.cpu"
904
905config HPET_TIMER
906	def_bool X86_64
907	prompt "HPET Timer Support" if X86_32
908	help
909	  Use the IA-PC HPET (High Precision Event Timer) to manage
910	  time in preference to the PIT and RTC, if a HPET is
911	  present.
912	  HPET is the next generation timer replacing legacy 8254s.
913	  The HPET provides a stable time base on SMP
914	  systems, unlike the TSC, but it is more expensive to access,
915	  as it is off-chip.  The interface used is documented
916	  in the HPET spec, revision 1.
917
918	  You can safely choose Y here.  However, HPET will only be
919	  activated if the platform and the BIOS support this feature.
920	  Otherwise the 8254 will be used for timing services.
921
922	  Choose N to continue using the legacy 8254 timer.
923
924config HPET_EMULATE_RTC
925	def_bool y
926	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
927
928# Mark as expert because too many people got it wrong.
929# The code disables itself when not needed.
930config DMI
931	default y
932	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
933	bool "Enable DMI scanning" if EXPERT
934	help
935	  Enabled scanning of DMI to identify machine quirks. Say Y
936	  here unless you have verified that your setup is not
937	  affected by entries in the DMI blacklist. Required by PNP
938	  BIOS code.
939
940config GART_IOMMU
941	bool "Old AMD GART IOMMU support"
942	select IOMMU_HELPER
943	select SWIOTLB
944	depends on X86_64 && PCI && AMD_NB
945	help
946	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
947	  GART based hardware IOMMUs.
948
949	  The GART supports full DMA access for devices with 32-bit access
950	  limitations, on systems with more than 3 GB. This is usually needed
951	  for USB, sound, many IDE/SATA chipsets and some other devices.
952
953	  Newer systems typically have a modern AMD IOMMU, supported via
954	  the CONFIG_AMD_IOMMU=y config option.
955
956	  In normal configurations this driver is only active when needed:
957	  there's more than 3 GB of memory and the system contains a
958	  32-bit limited device.
959
960	  If unsure, say Y.
961
962config BOOT_VESA_SUPPORT
963	bool
964	help
965	  If true, at least one selected framebuffer driver can take advantage
966	  of VESA video modes set at an early boot stage via the vga= parameter.
967
968config MAXSMP
969	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
970	depends on X86_64 && SMP && DEBUG_KERNEL
971	select CPUMASK_OFFSTACK
972	help
973	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
974	  If unsure, say N.
975
976#
977# The maximum number of CPUs supported:
978#
979# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
980# and which can be configured interactively in the
981# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
982#
983# The ranges are different on 32-bit and 64-bit kernels, depending on
984# hardware capabilities and scalability features of the kernel.
985#
986# ( If MAXSMP is enabled we just use the highest possible value and disable
987#   interactive configuration. )
988#
989
990config NR_CPUS_RANGE_BEGIN
991	int
992	default NR_CPUS_RANGE_END if MAXSMP
993	default    1 if !SMP
994	default    2
995
996config NR_CPUS_RANGE_END
997	int
998	depends on X86_32
999	default    8 if  SMP
1000	default    1 if !SMP
1001
1002config NR_CPUS_RANGE_END
1003	int
1004	depends on X86_64
1005	default 8192 if  SMP && CPUMASK_OFFSTACK
1006	default  512 if  SMP && !CPUMASK_OFFSTACK
1007	default    1 if !SMP
1008
1009config NR_CPUS_DEFAULT
1010	int
1011	depends on X86_32
1012	default    8 if  SMP
1013	default    1 if !SMP
1014
1015config NR_CPUS_DEFAULT
1016	int
1017	depends on X86_64
1018	default 8192 if  MAXSMP
1019	default   64 if  SMP
1020	default    1 if !SMP
1021
1022config NR_CPUS
1023	int "Maximum number of CPUs" if SMP && !MAXSMP
1024	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1025	default NR_CPUS_DEFAULT
1026	help
1027	  This allows you to specify the maximum number of CPUs which this
1028	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1029	  supported value is 8192, otherwise the maximum value is 512.  The
1030	  minimum value which makes sense is 2.
1031
1032	  This is purely to save memory: each supported CPU adds about 8KB
1033	  to the kernel image.
1034
1035config SCHED_CLUSTER
1036	bool "Cluster scheduler support"
1037	depends on SMP
1038	default y
1039	help
1040	  Cluster scheduler support improves the CPU scheduler's decision
1041	  making when dealing with machines that have clusters of CPUs.
1042	  Cluster usually means a couple of CPUs which are placed closely
1043	  by sharing mid-level caches, last-level cache tags or internal
1044	  busses.
1045
1046config SCHED_SMT
1047	def_bool y if SMP
1048
1049config SCHED_MC
1050	def_bool y
1051	prompt "Multi-core scheduler support"
1052	depends on SMP
1053	help
1054	  Multi-core scheduler support improves the CPU scheduler's decision
1055	  making when dealing with multi-core CPU chips at a cost of slightly
1056	  increased overhead in some places. If unsure say N here.
1057
1058config SCHED_MC_PRIO
1059	bool "CPU core priorities scheduler support"
1060	depends on SCHED_MC
1061	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1062	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1063	select CPU_FREQ
1064	default y
1065	help
1066	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1067	  core ordering determined at manufacturing time, which allows
1068	  certain cores to reach higher turbo frequencies (when running
1069	  single threaded workloads) than others.
1070
1071	  Enabling this kernel feature teaches the scheduler about
1072	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1073	  scheduler's CPU selection logic accordingly, so that higher
1074	  overall system performance can be achieved.
1075
1076	  This feature will have no effect on CPUs without this feature.
1077
1078	  If unsure say Y here.
1079
1080config UP_LATE_INIT
1081	def_bool y
1082	depends on !SMP && X86_LOCAL_APIC
1083
1084config X86_UP_APIC
1085	bool "Local APIC support on uniprocessors" if !PCI_MSI
1086	default PCI_MSI
1087	depends on X86_32 && !SMP
1088	help
1089	  A local APIC (Advanced Programmable Interrupt Controller) is an
1090	  integrated interrupt controller in the CPU. If you have a single-CPU
1091	  system which has a processor with a local APIC, you can say Y here to
1092	  enable and use it. If you say Y here even though your machine doesn't
1093	  have a local APIC, then the kernel will still run with no slowdown at
1094	  all. The local APIC supports CPU-generated self-interrupts (timer,
1095	  performance counters), and the NMI watchdog which detects hard
1096	  lockups.
1097
1098config X86_UP_IOAPIC
1099	bool "IO-APIC support on uniprocessors"
1100	depends on X86_UP_APIC
1101	help
1102	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1103	  SMP-capable replacement for PC-style interrupt controllers. Most
1104	  SMP systems and many recent uniprocessor systems have one.
1105
1106	  If you have a single-CPU system with an IO-APIC, you can say Y here
1107	  to use it. If you say Y here even though your machine doesn't have
1108	  an IO-APIC, then the kernel will still run with no slowdown at all.
1109
1110config X86_LOCAL_APIC
1111	def_bool y
1112	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1113	select IRQ_DOMAIN_HIERARCHY
1114
1115config ACPI_MADT_WAKEUP
1116	def_bool y
1117	depends on X86_64
1118	depends on ACPI
1119	depends on SMP
1120	depends on X86_LOCAL_APIC
1121
1122config X86_IO_APIC
1123	def_bool y
1124	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1125
1126config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1127	bool "Reroute for broken boot IRQs"
1128	depends on X86_IO_APIC
1129	help
1130	  This option enables a workaround that fixes a source of
1131	  spurious interrupts. This is recommended when threaded
1132	  interrupt handling is used on systems where the generation of
1133	  superfluous "boot interrupts" cannot be disabled.
1134
1135	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1136	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1137	  kernel does during interrupt handling). On chipsets where this
1138	  boot IRQ generation cannot be disabled, this workaround keeps
1139	  the original IRQ line masked so that only the equivalent "boot
1140	  IRQ" is delivered to the CPUs. The workaround also tells the
1141	  kernel to set up the IRQ handler on the boot IRQ line. In this
1142	  way only one interrupt is delivered to the kernel. Otherwise
1143	  the spurious second interrupt may cause the kernel to bring
1144	  down (vital) interrupt lines.
1145
1146	  Only affects "broken" chipsets. Interrupt sharing may be
1147	  increased on these systems.
1148
1149config X86_MCE
1150	bool "Machine Check / overheating reporting"
1151	select GENERIC_ALLOCATOR
1152	default y
1153	help
1154	  Machine Check support allows the processor to notify the
1155	  kernel if it detects a problem (e.g. overheating, data corruption).
1156	  The action the kernel takes depends on the severity of the problem,
1157	  ranging from warning messages to halting the machine.
1158
1159config X86_MCELOG_LEGACY
1160	bool "Support for deprecated /dev/mcelog character device"
1161	depends on X86_MCE
1162	help
1163	  Enable support for /dev/mcelog which is needed by the old mcelog
1164	  userspace logging daemon. Consider switching to the new generation
1165	  rasdaemon solution.
1166
1167config X86_MCE_INTEL
1168	def_bool y
1169	prompt "Intel MCE features"
1170	depends on X86_MCE && X86_LOCAL_APIC
1171	help
1172	  Additional support for intel specific MCE features such as
1173	  the thermal monitor.
1174
1175config X86_MCE_AMD
1176	def_bool y
1177	prompt "AMD MCE features"
1178	depends on X86_MCE && X86_LOCAL_APIC
1179	help
1180	  Additional support for AMD specific MCE features such as
1181	  the DRAM Error Threshold.
1182
1183config X86_ANCIENT_MCE
1184	bool "Support for old Pentium 5 / WinChip machine checks"
1185	depends on X86_32 && X86_MCE
1186	help
1187	  Include support for machine check handling on old Pentium 5 or WinChip
1188	  systems. These typically need to be enabled explicitly on the command
1189	  line.
1190
1191config X86_MCE_THRESHOLD
1192	depends on X86_MCE_AMD || X86_MCE_INTEL
1193	def_bool y
1194
1195config X86_MCE_INJECT
1196	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1197	tristate "Machine check injector support"
1198	help
1199	  Provide support for injecting machine checks for testing purposes.
1200	  If you don't know what a machine check is and you don't do kernel
1201	  QA it is safe to say n.
1202
1203source "arch/x86/events/Kconfig"
1204
1205config X86_LEGACY_VM86
1206	bool "Legacy VM86 support"
1207	depends on X86_32
1208	help
1209	  This option allows user programs to put the CPU into V8086
1210	  mode, which is an 80286-era approximation of 16-bit real mode.
1211
1212	  Some very old versions of X and/or vbetool require this option
1213	  for user mode setting.  Similarly, DOSEMU will use it if
1214	  available to accelerate real mode DOS programs.  However, any
1215	  recent version of DOSEMU, X, or vbetool should be fully
1216	  functional even without kernel VM86 support, as they will all
1217	  fall back to software emulation. Nevertheless, if you are using
1218	  a 16-bit DOS program where 16-bit performance matters, vm86
1219	  mode might be faster than emulation and you might want to
1220	  enable this option.
1221
1222	  Note that any app that works on a 64-bit kernel is unlikely to
1223	  need this option, as 64-bit kernels don't, and can't, support
1224	  V8086 mode. This option is also unrelated to 16-bit protected
1225	  mode and is not needed to run most 16-bit programs under Wine.
1226
1227	  Enabling this option increases the complexity of the kernel
1228	  and slows down exception handling a tiny bit.
1229
1230	  If unsure, say N here.
1231
1232config VM86
1233	bool
1234	default X86_LEGACY_VM86
1235
1236config X86_16BIT
1237	bool "Enable support for 16-bit segments" if EXPERT
1238	default y
1239	depends on MODIFY_LDT_SYSCALL
1240	help
1241	  This option is required by programs like Wine to run 16-bit
1242	  protected mode legacy code on x86 processors.  Disabling
1243	  this option saves about 300 bytes on i386, or around 6K text
1244	  plus 16K runtime memory on x86-64,
1245
1246config X86_ESPFIX32
1247	def_bool y
1248	depends on X86_16BIT && X86_32
1249
1250config X86_ESPFIX64
1251	def_bool y
1252	depends on X86_16BIT && X86_64
1253
1254config X86_VSYSCALL_EMULATION
1255	bool "Enable vsyscall emulation" if EXPERT
1256	default y
1257	depends on X86_64
1258	help
1259	  This enables emulation of the legacy vsyscall page.  Disabling
1260	  it is roughly equivalent to booting with vsyscall=none, except
1261	  that it will also disable the helpful warning if a program
1262	  tries to use a vsyscall.  With this option set to N, offending
1263	  programs will just segfault, citing addresses of the form
1264	  0xffffffffff600?00.
1265
1266	  This option is required by many programs built before 2013, and
1267	  care should be used even with newer programs if set to N.
1268
1269	  Disabling this option saves about 7K of kernel size and
1270	  possibly 4K of additional runtime pagetable memory.
1271
1272config X86_IOPL_IOPERM
1273	bool "IOPERM and IOPL Emulation"
1274	default y
1275	help
1276	  This enables the ioperm() and iopl() syscalls which are necessary
1277	  for legacy applications.
1278
1279	  Legacy IOPL support is an overbroad mechanism which allows user
1280	  space aside of accessing all 65536 I/O ports also to disable
1281	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1282	  capabilities and permission from potentially active security
1283	  modules.
1284
1285	  The emulation restricts the functionality of the syscall to
1286	  only allowing the full range I/O port access, but prevents the
1287	  ability to disable interrupts from user space which would be
1288	  granted if the hardware IOPL mechanism would be used.
1289
1290config TOSHIBA
1291	tristate "Toshiba Laptop support"
1292	depends on X86_32
1293	help
1294	  This adds a driver to safely access the System Management Mode of
1295	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1296	  not work on models with a Phoenix BIOS. The System Management Mode
1297	  is used to set the BIOS and power saving options on Toshiba portables.
1298
1299	  For information on utilities to make use of this driver see the
1300	  Toshiba Linux utilities web site at:
1301	  <http://www.buzzard.org.uk/toshiba/>.
1302
1303	  Say Y if you intend to run this kernel on a Toshiba portable.
1304	  Say N otherwise.
1305
1306config X86_REBOOTFIXUPS
1307	bool "Enable X86 board specific fixups for reboot"
1308	depends on X86_32
1309	help
1310	  This enables chipset and/or board specific fixups to be done
1311	  in order to get reboot to work correctly. This is only needed on
1312	  some combinations of hardware and BIOS. The symptom, for which
1313	  this config is intended, is when reboot ends with a stalled/hung
1314	  system.
1315
1316	  Currently, the only fixup is for the Geode machines using
1317	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1318
1319	  Say Y if you want to enable the fixup. Currently, it's safe to
1320	  enable this option even if you don't need it.
1321	  Say N otherwise.
1322
1323config MICROCODE
1324	def_bool y
1325	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1326	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1327
1328config MICROCODE_INITRD32
1329	def_bool y
1330	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1331
1332config MICROCODE_LATE_LOADING
1333	bool "Late microcode loading (DANGEROUS)"
1334	default n
1335	depends on MICROCODE && SMP
1336	help
1337	  Loading microcode late, when the system is up and executing instructions
1338	  is a tricky business and should be avoided if possible. Just the sequence
1339	  of synchronizing all cores and SMT threads is one fragile dance which does
1340	  not guarantee that cores might not softlock after the loading. Therefore,
1341	  use this at your own risk. Late loading taints the kernel unless the
1342	  microcode header indicates that it is safe for late loading via the
1343	  minimal revision check. This minimal revision check can be enforced on
1344	  the kernel command line with "microcode.minrev=Y".
1345
1346config MICROCODE_LATE_FORCE_MINREV
1347	bool "Enforce late microcode loading minimal revision check"
1348	default n
1349	depends on MICROCODE_LATE_LOADING
1350	help
1351	  To prevent that users load microcode late which modifies already
1352	  in use features, newer microcode patches have a minimum revision field
1353	  in the microcode header, which tells the kernel which minimum
1354	  revision must be active in the CPU to safely load that new microcode
1355	  late into the running system. If disabled the check will not
1356	  be enforced but the kernel will be tainted when the minimal
1357	  revision check fails.
1358
1359	  This minimal revision check can also be controlled via the
1360	  "microcode.minrev" parameter on the kernel command line.
1361
1362	  If unsure say Y.
1363
1364config X86_MSR
1365	tristate "/dev/cpu/*/msr - Model-specific register support"
1366	help
1367	  This device gives privileged processes access to the x86
1368	  Model-Specific Registers (MSRs).  It is a character device with
1369	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1370	  MSR accesses are directed to a specific CPU on multi-processor
1371	  systems.
1372
1373config X86_CPUID
1374	tristate "/dev/cpu/*/cpuid - CPU information support"
1375	help
1376	  This device gives processes access to the x86 CPUID instruction to
1377	  be executed on a specific processor.  It is a character device
1378	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1379	  /dev/cpu/31/cpuid.
1380
1381config HIGHMEM4G
1382	bool "High Memory Support"
1383	depends on X86_32
1384	help
1385	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1386	  However, the address space of 32-bit x86 processors is only 4
1387	  Gigabytes large. That means that, if you have a large amount of
1388	  physical memory, not all of it can be "permanently mapped" by the
1389	  kernel. The physical memory that's not permanently mapped is called
1390	  "high memory".
1391
1392	  If you are compiling a kernel which will never run on a machine with
1393	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1394	  choice and suitable for most users). This will result in a "3GB/1GB"
1395	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1396	  space and the remaining part of the 4GB virtual memory space is used
1397	  by the kernel to permanently map as much physical memory as
1398	  possible.
1399
1400	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1401	  answer "Y" here.
1402
1403	  If unsure, say N.
1404
1405choice
1406	prompt "Memory split" if EXPERT
1407	default VMSPLIT_3G
1408	depends on X86_32
1409	help
1410	  Select the desired split between kernel and user memory.
1411
1412	  If the address range available to the kernel is less than the
1413	  physical memory installed, the remaining memory will be available
1414	  as "high memory". Accessing high memory is a little more costly
1415	  than low memory, as it needs to be mapped into the kernel first.
1416	  Note that increasing the kernel address space limits the range
1417	  available to user programs, making the address space there
1418	  tighter.  Selecting anything other than the default 3G/1G split
1419	  will also likely make your kernel incompatible with binary-only
1420	  kernel modules.
1421
1422	  If you are not absolutely sure what you are doing, leave this
1423	  option alone!
1424
1425	config VMSPLIT_3G
1426		bool "3G/1G user/kernel split"
1427	config VMSPLIT_3G_OPT
1428		depends on !X86_PAE
1429		bool "3G/1G user/kernel split (for full 1G low memory)"
1430	config VMSPLIT_2G
1431		bool "2G/2G user/kernel split"
1432	config VMSPLIT_2G_OPT
1433		depends on !X86_PAE
1434		bool "2G/2G user/kernel split (for full 2G low memory)"
1435	config VMSPLIT_1G
1436		bool "1G/3G user/kernel split"
1437endchoice
1438
1439config PAGE_OFFSET
1440	hex
1441	default 0xB0000000 if VMSPLIT_3G_OPT
1442	default 0x80000000 if VMSPLIT_2G
1443	default 0x78000000 if VMSPLIT_2G_OPT
1444	default 0x40000000 if VMSPLIT_1G
1445	default 0xC0000000
1446	depends on X86_32
1447
1448config HIGHMEM
1449	def_bool HIGHMEM4G
1450
1451config X86_PAE
1452	bool "PAE (Physical Address Extension) Support"
1453	depends on X86_32 && X86_HAVE_PAE
1454	select PHYS_ADDR_T_64BIT
1455	help
1456	  PAE is required for NX support, and furthermore enables
1457	  larger swapspace support for non-overcommit purposes. It
1458	  has the cost of more pagetable lookup overhead, and also
1459	  consumes more pagetable space per process.
1460
1461config X86_DIRECT_GBPAGES
1462	def_bool y
1463	depends on X86_64
1464	help
1465	  Certain kernel features effectively disable kernel
1466	  linear 1 GB mappings (even if the CPU otherwise
1467	  supports them), so don't confuse the user by printing
1468	  that we have them enabled.
1469
1470config X86_CPA_STATISTICS
1471	bool "Enable statistic for Change Page Attribute"
1472	depends on DEBUG_FS
1473	help
1474	  Expose statistics about the Change Page Attribute mechanism, which
1475	  helps to determine the effectiveness of preserving large and huge
1476	  page mappings when mapping protections are changed.
1477
1478config X86_MEM_ENCRYPT
1479	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1480	select DYNAMIC_PHYSICAL_MASK
1481	def_bool n
1482
1483config AMD_MEM_ENCRYPT
1484	bool "AMD Secure Memory Encryption (SME) support"
1485	depends on X86_64 && CPU_SUP_AMD
1486	depends on EFI_STUB
1487	select DMA_COHERENT_POOL
1488	select ARCH_USE_MEMREMAP_PROT
1489	select INSTRUCTION_DECODER
1490	select ARCH_HAS_CC_PLATFORM
1491	select X86_MEM_ENCRYPT
1492	select UNACCEPTED_MEMORY
1493	select CRYPTO_LIB_AESGCM
1494	help
1495	  Say yes to enable support for the encryption of system memory.
1496	  This requires an AMD processor that supports Secure Memory
1497	  Encryption (SME).
1498
1499# Common NUMA Features
1500config NUMA
1501	bool "NUMA Memory Allocation and Scheduler Support"
1502	depends on SMP
1503	depends on X86_64
1504	select USE_PERCPU_NUMA_NODE_ID
1505	select OF_NUMA if OF
1506	help
1507	  Enable NUMA (Non-Uniform Memory Access) support.
1508
1509	  The kernel will try to allocate memory used by a CPU on the
1510	  local memory controller of the CPU and add some more
1511	  NUMA awareness to the kernel.
1512
1513	  For 64-bit this is recommended if the system is Intel Core i7
1514	  (or later), AMD Opteron, or EM64T NUMA.
1515
1516	  Otherwise, you should say N.
1517
1518config AMD_NUMA
1519	def_bool y
1520	prompt "Old style AMD Opteron NUMA detection"
1521	depends on X86_64 && NUMA && PCI
1522	help
1523	  Enable AMD NUMA node topology detection.  You should say Y here if
1524	  you have a multi processor AMD system. This uses an old method to
1525	  read the NUMA configuration directly from the builtin Northbridge
1526	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1527	  which also takes priority if both are compiled in.
1528
1529config X86_64_ACPI_NUMA
1530	def_bool y
1531	prompt "ACPI NUMA detection"
1532	depends on X86_64 && NUMA && ACPI && PCI
1533	select ACPI_NUMA
1534	help
1535	  Enable ACPI SRAT based node topology detection.
1536
1537config NODES_SHIFT
1538	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1539	range 1 10
1540	default "10" if MAXSMP
1541	default "6" if X86_64
1542	default "3"
1543	depends on NUMA
1544	help
1545	  Specify the maximum number of NUMA Nodes available on the target
1546	  system.  Increases memory reserved to accommodate various tables.
1547
1548config ARCH_FLATMEM_ENABLE
1549	def_bool y
1550	depends on X86_32 && !NUMA
1551
1552config ARCH_SPARSEMEM_ENABLE
1553	def_bool y
1554	select SPARSEMEM_STATIC if X86_32
1555	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1556	select SPARSEMEM_VMEMMAP if X86_64
1557
1558config ARCH_SPARSEMEM_DEFAULT
1559	def_bool X86_64 || (NUMA && X86_32)
1560
1561config ARCH_SELECT_MEMORY_MODEL
1562	def_bool y
1563	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1564
1565config ARCH_MEMORY_PROBE
1566	bool "Enable sysfs memory/probe interface"
1567	depends on MEMORY_HOTPLUG
1568	help
1569	  This option enables a sysfs memory/probe interface for testing.
1570	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1571	  If you are unsure how to answer this question, answer N.
1572
1573config ARCH_PROC_KCORE_TEXT
1574	def_bool y
1575	depends on X86_64 && PROC_KCORE
1576
1577config ILLEGAL_POINTER_VALUE
1578	hex
1579	default 0 if X86_32
1580	default 0xdead000000000000 if X86_64
1581
1582config X86_PMEM_LEGACY_DEVICE
1583	bool
1584
1585config X86_PMEM_LEGACY
1586	tristate "Support non-standard NVDIMMs and ADR protected memory"
1587	depends on PHYS_ADDR_T_64BIT
1588	depends on BLK_DEV
1589	select X86_PMEM_LEGACY_DEVICE
1590	select NUMA_KEEP_MEMINFO if NUMA
1591	select LIBNVDIMM
1592	help
1593	  Treat memory marked using the non-standard e820 type of 12 as used
1594	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1595	  The kernel will offer these regions to the 'pmem' driver so
1596	  they can be used for persistent storage.
1597
1598	  Say Y if unsure.
1599
1600config X86_CHECK_BIOS_CORRUPTION
1601	bool "Check for low memory corruption"
1602	help
1603	  Periodically check for memory corruption in low memory, which
1604	  is suspected to be caused by BIOS.  Even when enabled in the
1605	  configuration, it is disabled at runtime.  Enable it by
1606	  setting "memory_corruption_check=1" on the kernel command
1607	  line.  By default it scans the low 64k of memory every 60
1608	  seconds; see the memory_corruption_check_size and
1609	  memory_corruption_check_period parameters in
1610	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1611
1612	  When enabled with the default parameters, this option has
1613	  almost no overhead, as it reserves a relatively small amount
1614	  of memory and scans it infrequently.  It both detects corruption
1615	  and prevents it from affecting the running system.
1616
1617	  It is, however, intended as a diagnostic tool; if repeatable
1618	  BIOS-originated corruption always affects the same memory,
1619	  you can use memmap= to prevent the kernel from using that
1620	  memory.
1621
1622config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1623	bool "Set the default setting of memory_corruption_check"
1624	depends on X86_CHECK_BIOS_CORRUPTION
1625	default y
1626	help
1627	  Set whether the default state of memory_corruption_check is
1628	  on or off.
1629
1630config MATH_EMULATION
1631	bool
1632	depends on MODIFY_LDT_SYSCALL
1633	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1634	help
1635	  Linux can emulate a math coprocessor (used for floating point
1636	  operations) if you don't have one. 486DX and Pentium processors have
1637	  a math coprocessor built in, 486SX and 386 do not, unless you added
1638	  a 487DX or 387, respectively. (The messages during boot time can
1639	  give you some hints here ["man dmesg"].) Everyone needs either a
1640	  coprocessor or this emulation.
1641
1642	  If you don't have a math coprocessor, you need to say Y here; if you
1643	  say Y here even though you have a coprocessor, the coprocessor will
1644	  be used nevertheless. (This behavior can be changed with the kernel
1645	  command line option "no387", which comes handy if your coprocessor
1646	  is broken. Try "man bootparam" or see the documentation of your boot
1647	  loader (lilo or loadlin) about how to pass options to the kernel at
1648	  boot time.) This means that it is a good idea to say Y here if you
1649	  intend to use this kernel on different machines.
1650
1651	  More information about the internals of the Linux math coprocessor
1652	  emulation can be found in <file:arch/x86/math-emu/README>.
1653
1654	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1655	  kernel, it won't hurt.
1656
1657config MTRR
1658	def_bool y
1659	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1660	help
1661	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1662	  the Memory Type Range Registers (MTRRs) may be used to control
1663	  processor access to memory ranges. This is most useful if you have
1664	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1665	  allows bus write transfers to be combined into a larger transfer
1666	  before bursting over the PCI/AGP bus. This can increase performance
1667	  of image write operations 2.5 times or more. Saying Y here creates a
1668	  /proc/mtrr file which may be used to manipulate your processor's
1669	  MTRRs. Typically the X server should use this.
1670
1671	  This code has a reasonably generic interface so that similar
1672	  control registers on other processors can be easily supported
1673	  as well:
1674
1675	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1676	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1677	  these, the ARRs are used to emulate the MTRRs.
1678	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1679	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1680	  write-combining. All of these processors are supported by this code
1681	  and it makes sense to say Y here if you have one of them.
1682
1683	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1684	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1685	  can lead to all sorts of problems, so it's good to say Y here.
1686
1687	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1688	  just add about 9 KB to your kernel.
1689
1690	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1691
1692config MTRR_SANITIZER
1693	def_bool y
1694	prompt "MTRR cleanup support"
1695	depends on MTRR
1696	help
1697	  Convert MTRR layout from continuous to discrete, so X drivers can
1698	  add writeback entries.
1699
1700	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1701	  The largest mtrr entry size for a continuous block can be set with
1702	  mtrr_chunk_size.
1703
1704	  If unsure, say Y.
1705
1706config MTRR_SANITIZER_ENABLE_DEFAULT
1707	int "MTRR cleanup enable value (0-1)"
1708	range 0 1
1709	default "0"
1710	depends on MTRR_SANITIZER
1711	help
1712	  Enable mtrr cleanup default value
1713
1714config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1715	int "MTRR cleanup spare reg num (0-7)"
1716	range 0 7
1717	default "1"
1718	depends on MTRR_SANITIZER
1719	help
1720	  mtrr cleanup spare entries default, it can be changed via
1721	  mtrr_spare_reg_nr=N on the kernel command line.
1722
1723config X86_PAT
1724	def_bool y
1725	prompt "x86 PAT support" if EXPERT
1726	depends on MTRR
1727	select ARCH_USES_PG_ARCH_2
1728	help
1729	  Use PAT attributes to setup page level cache control.
1730
1731	  PATs are the modern equivalents of MTRRs and are much more
1732	  flexible than MTRRs.
1733
1734	  Say N here if you see bootup problems (boot crash, boot hang,
1735	  spontaneous reboots) or a non-working video driver.
1736
1737	  If unsure, say Y.
1738
1739config X86_UMIP
1740	def_bool y
1741	prompt "User Mode Instruction Prevention" if EXPERT
1742	help
1743	  User Mode Instruction Prevention (UMIP) is a security feature in
1744	  some x86 processors. If enabled, a general protection fault is
1745	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1746	  executed in user mode. These instructions unnecessarily expose
1747	  information about the hardware state.
1748
1749	  The vast majority of applications do not use these instructions.
1750	  For the very few that do, software emulation is provided in
1751	  specific cases in protected and virtual-8086 modes. Emulated
1752	  results are dummy.
1753
1754config CC_HAS_IBT
1755	# GCC >= 9 and binutils >= 2.29
1756	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1757	# Clang/LLVM >= 14
1758	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1759	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1760	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1761		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1762		  $(as-instr,endbr64)
1763
1764config X86_CET
1765	def_bool n
1766	help
1767	  CET features configured (Shadow stack or IBT)
1768
1769config X86_KERNEL_IBT
1770	prompt "Indirect Branch Tracking"
1771	def_bool y
1772	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1773	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1774	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1775	select OBJTOOL
1776	select X86_CET
1777	help
1778	  Build the kernel with support for Indirect Branch Tracking, a
1779	  hardware support course-grain forward-edge Control Flow Integrity
1780	  protection. It enforces that all indirect calls must land on
1781	  an ENDBR instruction, as such, the compiler will instrument the
1782	  code with them to make this happen.
1783
1784	  In addition to building the kernel with IBT, seal all functions that
1785	  are not indirect call targets, avoiding them ever becoming one.
1786
1787	  This requires LTO like objtool runs and will slow down the build. It
1788	  does significantly reduce the number of ENDBR instructions in the
1789	  kernel image.
1790
1791config X86_INTEL_MEMORY_PROTECTION_KEYS
1792	prompt "Memory Protection Keys"
1793	def_bool y
1794	# Note: only available in 64-bit mode
1795	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1796	select ARCH_USES_HIGH_VMA_FLAGS
1797	select ARCH_HAS_PKEYS
1798	help
1799	  Memory Protection Keys provides a mechanism for enforcing
1800	  page-based protections, but without requiring modification of the
1801	  page tables when an application changes protection domains.
1802
1803	  For details, see Documentation/core-api/protection-keys.rst
1804
1805	  If unsure, say y.
1806
1807config ARCH_PKEY_BITS
1808	int
1809	default 4
1810
1811choice
1812	prompt "TSX enable mode"
1813	depends on CPU_SUP_INTEL
1814	default X86_INTEL_TSX_MODE_OFF
1815	help
1816	  Intel's TSX (Transactional Synchronization Extensions) feature
1817	  allows to optimize locking protocols through lock elision which
1818	  can lead to a noticeable performance boost.
1819
1820	  On the other hand it has been shown that TSX can be exploited
1821	  to form side channel attacks (e.g. TAA) and chances are there
1822	  will be more of those attacks discovered in the future.
1823
1824	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1825	  might override this decision by tsx=on the command line parameter.
1826	  Even with TSX enabled, the kernel will attempt to enable the best
1827	  possible TAA mitigation setting depending on the microcode available
1828	  for the particular machine.
1829
1830	  This option allows to set the default tsx mode between tsx=on, =off
1831	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1832	  details.
1833
1834	  Say off if not sure, auto if TSX is in use but it should be used on safe
1835	  platforms or on if TSX is in use and the security aspect of tsx is not
1836	  relevant.
1837
1838config X86_INTEL_TSX_MODE_OFF
1839	bool "off"
1840	help
1841	  TSX is disabled if possible - equals to tsx=off command line parameter.
1842
1843config X86_INTEL_TSX_MODE_ON
1844	bool "on"
1845	help
1846	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1847	  line parameter.
1848
1849config X86_INTEL_TSX_MODE_AUTO
1850	bool "auto"
1851	help
1852	  TSX is enabled on TSX capable HW that is believed to be safe against
1853	  side channel attacks- equals the tsx=auto command line parameter.
1854endchoice
1855
1856config X86_SGX
1857	bool "Software Guard eXtensions (SGX)"
1858	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1859	select CRYPTO_LIB_SHA256
1860	select MMU_NOTIFIER
1861	select NUMA_KEEP_MEMINFO if NUMA
1862	select XARRAY_MULTI
1863	help
1864	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1865	  that can be used by applications to set aside private regions of code
1866	  and data, referred to as enclaves. An enclave's private memory can
1867	  only be accessed by code running within the enclave. Accesses from
1868	  outside the enclave, including other enclaves, are disallowed by
1869	  hardware.
1870
1871	  If unsure, say N.
1872
1873config X86_USER_SHADOW_STACK
1874	bool "X86 userspace shadow stack"
1875	depends on AS_WRUSS
1876	depends on X86_64
1877	select ARCH_USES_HIGH_VMA_FLAGS
1878	select ARCH_HAS_USER_SHADOW_STACK
1879	select X86_CET
1880	help
1881	  Shadow stack protection is a hardware feature that detects function
1882	  return address corruption.  This helps mitigate ROP attacks.
1883	  Applications must be enabled to use it, and old userspace does not
1884	  get protection "for free".
1885
1886	  CPUs supporting shadow stacks were first released in 2020.
1887
1888	  See Documentation/arch/x86/shstk.rst for more information.
1889
1890	  If unsure, say N.
1891
1892config INTEL_TDX_HOST
1893	bool "Intel Trust Domain Extensions (TDX) host support"
1894	depends on CPU_SUP_INTEL
1895	depends on X86_64
1896	depends on KVM_INTEL
1897	depends on X86_X2APIC
1898	select ARCH_KEEP_MEMBLOCK
1899	depends on CONTIG_ALLOC
1900	depends on !KEXEC_CORE
1901	depends on X86_MCE
1902	help
1903	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1904	  host and certain physical attacks.  This option enables necessary TDX
1905	  support in the host kernel to run confidential VMs.
1906
1907	  If unsure, say N.
1908
1909config EFI
1910	bool "EFI runtime service support"
1911	depends on ACPI
1912	select UCS2_STRING
1913	select EFI_RUNTIME_WRAPPERS
1914	select ARCH_USE_MEMREMAP_PROT
1915	select EFI_RUNTIME_MAP if KEXEC_CORE
1916	help
1917	  This enables the kernel to use EFI runtime services that are
1918	  available (such as the EFI variable services).
1919
1920	  This option is only useful on systems that have EFI firmware.
1921	  In addition, you should use the latest ELILO loader available
1922	  at <http://elilo.sourceforge.net> in order to take advantage
1923	  of EFI runtime services. However, even with this option, the
1924	  resultant kernel should continue to boot on existing non-EFI
1925	  platforms.
1926
1927config EFI_STUB
1928	bool "EFI stub support"
1929	depends on EFI
1930	select RELOCATABLE
1931	help
1932	  This kernel feature allows a bzImage to be loaded directly
1933	  by EFI firmware without the use of a bootloader.
1934
1935	  See Documentation/admin-guide/efi-stub.rst for more information.
1936
1937config EFI_HANDOVER_PROTOCOL
1938	bool "EFI handover protocol (DEPRECATED)"
1939	depends on EFI_STUB
1940	default y
1941	help
1942	  Select this in order to include support for the deprecated EFI
1943	  handover protocol, which defines alternative entry points into the
1944	  EFI stub.  This is a practice that has no basis in the UEFI
1945	  specification, and requires a priori knowledge on the part of the
1946	  bootloader about Linux/x86 specific ways of passing the command line
1947	  and initrd, and where in memory those assets may be loaded.
1948
1949	  If in doubt, say Y. Even though the corresponding support is not
1950	  present in upstream GRUB or other bootloaders, most distros build
1951	  GRUB with numerous downstream patches applied, and may rely on the
1952	  handover protocol as as result.
1953
1954config EFI_MIXED
1955	bool "EFI mixed-mode support"
1956	depends on EFI_STUB && X86_64
1957	help
1958	  Enabling this feature allows a 64-bit kernel to be booted
1959	  on a 32-bit firmware, provided that your CPU supports 64-bit
1960	  mode.
1961
1962	  Note that it is not possible to boot a mixed-mode enabled
1963	  kernel via the EFI boot stub - a bootloader that supports
1964	  the EFI handover protocol must be used.
1965
1966	  If unsure, say N.
1967
1968config EFI_RUNTIME_MAP
1969	bool "Export EFI runtime maps to sysfs" if EXPERT
1970	depends on EFI
1971	help
1972	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1973	  That memory map is required by the 2nd kernel to set up EFI virtual
1974	  mappings after kexec, but can also be used for debugging purposes.
1975
1976	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1977
1978source "kernel/Kconfig.hz"
1979
1980config ARCH_SUPPORTS_KEXEC
1981	def_bool y
1982
1983config ARCH_SUPPORTS_KEXEC_FILE
1984	def_bool X86_64
1985
1986config ARCH_SELECTS_KEXEC_FILE
1987	def_bool y
1988	depends on KEXEC_FILE
1989	select HAVE_IMA_KEXEC if IMA
1990
1991config ARCH_SUPPORTS_KEXEC_PURGATORY
1992	def_bool y
1993
1994config ARCH_SUPPORTS_KEXEC_SIG
1995	def_bool y
1996
1997config ARCH_SUPPORTS_KEXEC_SIG_FORCE
1998	def_bool y
1999
2000config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2001	def_bool y
2002
2003config ARCH_SUPPORTS_KEXEC_JUMP
2004	def_bool y
2005
2006config ARCH_SUPPORTS_KEXEC_HANDOVER
2007	def_bool X86_64
2008
2009config ARCH_SUPPORTS_CRASH_DUMP
2010	def_bool X86_64 || (X86_32 && HIGHMEM)
2011
2012config ARCH_DEFAULT_CRASH_DUMP
2013	def_bool y
2014
2015config ARCH_SUPPORTS_CRASH_HOTPLUG
2016	def_bool y
2017
2018config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2019	def_bool CRASH_RESERVE
2020
2021config PHYSICAL_START
2022	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2023	default "0x1000000"
2024	help
2025	  This gives the physical address where the kernel is loaded.
2026
2027	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2028	  will decompress itself to above physical address and run from there.
2029	  Otherwise, bzImage will run from the address where it has been loaded
2030	  by the boot loader. The only exception is if it is loaded below the
2031	  above physical address, in which case it will relocate itself there.
2032
2033	  In normal kdump cases one does not have to set/change this option
2034	  as now bzImage can be compiled as a completely relocatable image
2035	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2036	  address. This option is mainly useful for the folks who don't want
2037	  to use a bzImage for capturing the crash dump and want to use a
2038	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2039	  to be specifically compiled to run from a specific memory area
2040	  (normally a reserved region) and this option comes handy.
2041
2042	  So if you are using bzImage for capturing the crash dump,
2043	  leave the value here unchanged to 0x1000000 and set
2044	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2045	  for capturing the crash dump change this value to start of
2046	  the reserved region.  In other words, it can be set based on
2047	  the "X" value as specified in the "crashkernel=YM@XM"
2048	  command line boot parameter passed to the panic-ed
2049	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2050	  for more details about crash dumps.
2051
2052	  Usage of bzImage for capturing the crash dump is recommended as
2053	  one does not have to build two kernels. Same kernel can be used
2054	  as production kernel and capture kernel. Above option should have
2055	  gone away after relocatable bzImage support is introduced. But it
2056	  is present because there are users out there who continue to use
2057	  vmlinux for dump capture. This option should go away down the
2058	  line.
2059
2060	  Don't change this unless you know what you are doing.
2061
2062config RELOCATABLE
2063	bool "Build a relocatable kernel"
2064	default y
2065	help
2066	  This builds a kernel image that retains relocation information
2067	  so it can be loaded someplace besides the default 1MB.
2068	  The relocations tend to make the kernel binary about 10% larger,
2069	  but are discarded at runtime.
2070
2071	  One use is for the kexec on panic case where the recovery kernel
2072	  must live at a different physical address than the primary
2073	  kernel.
2074
2075	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2076	  it has been loaded at and the compile time physical address
2077	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2078
2079config RANDOMIZE_BASE
2080	bool "Randomize the address of the kernel image (KASLR)"
2081	depends on RELOCATABLE
2082	default y
2083	help
2084	  In support of Kernel Address Space Layout Randomization (KASLR),
2085	  this randomizes the physical address at which the kernel image
2086	  is decompressed and the virtual address where the kernel
2087	  image is mapped, as a security feature that deters exploit
2088	  attempts relying on knowledge of the location of kernel
2089	  code internals.
2090
2091	  On 64-bit, the kernel physical and virtual addresses are
2092	  randomized separately. The physical address will be anywhere
2093	  between 16MB and the top of physical memory (up to 64TB). The
2094	  virtual address will be randomized from 16MB up to 1GB (9 bits
2095	  of entropy). Note that this also reduces the memory space
2096	  available to kernel modules from 1.5GB to 1GB.
2097
2098	  On 32-bit, the kernel physical and virtual addresses are
2099	  randomized together. They will be randomized from 16MB up to
2100	  512MB (8 bits of entropy).
2101
2102	  Entropy is generated using the RDRAND instruction if it is
2103	  supported. If RDTSC is supported, its value is mixed into
2104	  the entropy pool as well. If neither RDRAND nor RDTSC are
2105	  supported, then entropy is read from the i8254 timer. The
2106	  usable entropy is limited by the kernel being built using
2107	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2108	  minimum of 2MB. As a result, only 10 bits of entropy are
2109	  theoretically possible, but the implementations are further
2110	  limited due to memory layouts.
2111
2112	  If unsure, say Y.
2113
2114# Relocation on x86 needs some additional build support
2115config X86_NEED_RELOCS
2116	def_bool y
2117	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2118	select ARCH_VMLINUX_NEEDS_RELOCS
2119
2120config PHYSICAL_ALIGN
2121	hex "Alignment value to which kernel should be aligned"
2122	default "0x200000"
2123	range 0x2000 0x1000000 if X86_32
2124	range 0x200000 0x1000000 if X86_64
2125	help
2126	  This value puts the alignment restrictions on physical address
2127	  where kernel is loaded and run from. Kernel is compiled for an
2128	  address which meets above alignment restriction.
2129
2130	  If bootloader loads the kernel at a non-aligned address and
2131	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2132	  address aligned to above value and run from there.
2133
2134	  If bootloader loads the kernel at a non-aligned address and
2135	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2136	  load address and decompress itself to the address it has been
2137	  compiled for and run from there. The address for which kernel is
2138	  compiled already meets above alignment restrictions. Hence the
2139	  end result is that kernel runs from a physical address meeting
2140	  above alignment restrictions.
2141
2142	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2143	  this value must be a multiple of 0x200000.
2144
2145	  Don't change this unless you know what you are doing.
2146
2147config RANDOMIZE_MEMORY
2148	bool "Randomize the kernel memory sections"
2149	depends on X86_64
2150	depends on RANDOMIZE_BASE
2151	default RANDOMIZE_BASE
2152	help
2153	  Randomizes the base virtual address of kernel memory sections
2154	  (physical memory mapping, vmalloc & vmemmap). This security feature
2155	  makes exploits relying on predictable memory locations less reliable.
2156
2157	  The order of allocations remains unchanged. Entropy is generated in
2158	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2159	  configuration have in average 30,000 different possible virtual
2160	  addresses for each memory section.
2161
2162	  If unsure, say Y.
2163
2164config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2165	hex "Physical memory mapping padding" if EXPERT
2166	depends on RANDOMIZE_MEMORY
2167	default "0xa" if MEMORY_HOTPLUG
2168	default "0x0"
2169	range 0x1 0x40 if MEMORY_HOTPLUG
2170	range 0x0 0x40
2171	help
2172	  Define the padding in terabytes added to the existing physical
2173	  memory size during kernel memory randomization. It is useful
2174	  for memory hotplug support but reduces the entropy available for
2175	  address randomization.
2176
2177	  If unsure, leave at the default value.
2178
2179config ADDRESS_MASKING
2180	bool "Linear Address Masking support"
2181	depends on X86_64
2182	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2183	help
2184	  Linear Address Masking (LAM) modifies the checking that is applied
2185	  to 64-bit linear addresses, allowing software to use of the
2186	  untranslated address bits for metadata.
2187
2188	  The capability can be used for efficient address sanitizers (ASAN)
2189	  implementation and for optimizations in JITs.
2190
2191config HOTPLUG_CPU
2192	def_bool y
2193	depends on SMP
2194
2195config COMPAT_VDSO
2196	def_bool n
2197	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2198	depends on COMPAT_32
2199	help
2200	  Certain buggy versions of glibc will crash if they are
2201	  presented with a 32-bit vDSO that is not mapped at the address
2202	  indicated in its segment table.
2203
2204	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2205	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2206	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2207	  the only released version with the bug, but OpenSUSE 9
2208	  contains a buggy "glibc 2.3.2".
2209
2210	  The symptom of the bug is that everything crashes on startup, saying:
2211	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2212
2213	  Saying Y here changes the default value of the vdso32 boot
2214	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2215	  This works around the glibc bug but hurts performance.
2216
2217	  If unsure, say N: if you are compiling your own kernel, you
2218	  are unlikely to be using a buggy version of glibc.
2219
2220choice
2221	prompt "vsyscall table for legacy applications"
2222	depends on X86_64
2223	default LEGACY_VSYSCALL_XONLY
2224	help
2225	  Legacy user code that does not know how to find the vDSO expects
2226	  to be able to issue three syscalls by calling fixed addresses in
2227	  kernel space. Since this location is not randomized with ASLR,
2228	  it can be used to assist security vulnerability exploitation.
2229
2230	  This setting can be changed at boot time via the kernel command
2231	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2232	  is deprecated and can only be enabled using the kernel command
2233	  line.
2234
2235	  On a system with recent enough glibc (2.14 or newer) and no
2236	  static binaries, you can say None without a performance penalty
2237	  to improve security.
2238
2239	  If unsure, select "Emulate execution only".
2240
2241	config LEGACY_VSYSCALL_XONLY
2242		bool "Emulate execution only"
2243		help
2244		  The kernel traps and emulates calls into the fixed vsyscall
2245		  address mapping and does not allow reads.  This
2246		  configuration is recommended when userspace might use the
2247		  legacy vsyscall area but support for legacy binary
2248		  instrumentation of legacy code is not needed.  It mitigates
2249		  certain uses of the vsyscall area as an ASLR-bypassing
2250		  buffer.
2251
2252	config LEGACY_VSYSCALL_NONE
2253		bool "None"
2254		help
2255		  There will be no vsyscall mapping at all. This will
2256		  eliminate any risk of ASLR bypass due to the vsyscall
2257		  fixed address mapping. Attempts to use the vsyscalls
2258		  will be reported to dmesg, so that either old or
2259		  malicious userspace programs can be identified.
2260
2261endchoice
2262
2263config CMDLINE_BOOL
2264	bool "Built-in kernel command line"
2265	help
2266	  Allow for specifying boot arguments to the kernel at
2267	  build time.  On some systems (e.g. embedded ones), it is
2268	  necessary or convenient to provide some or all of the
2269	  kernel boot arguments with the kernel itself (that is,
2270	  to not rely on the boot loader to provide them.)
2271
2272	  To compile command line arguments into the kernel,
2273	  set this option to 'Y', then fill in the
2274	  boot arguments in CONFIG_CMDLINE.
2275
2276	  Systems with fully functional boot loaders (i.e. non-embedded)
2277	  should leave this option set to 'N'.
2278
2279config CMDLINE
2280	string "Built-in kernel command string"
2281	depends on CMDLINE_BOOL
2282	default ""
2283	help
2284	  Enter arguments here that should be compiled into the kernel
2285	  image and used at boot time.  If the boot loader provides a
2286	  command line at boot time, it is appended to this string to
2287	  form the full kernel command line, when the system boots.
2288
2289	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2290	  change this behavior.
2291
2292	  In most cases, the command line (whether built-in or provided
2293	  by the boot loader) should specify the device for the root
2294	  file system.
2295
2296config CMDLINE_OVERRIDE
2297	bool "Built-in command line overrides boot loader arguments"
2298	depends on CMDLINE_BOOL && CMDLINE != ""
2299	help
2300	  Set this option to 'Y' to have the kernel ignore the boot loader
2301	  command line, and use ONLY the built-in command line.
2302
2303	  This is used to work around broken boot loaders.  This should
2304	  be set to 'N' under normal conditions.
2305
2306config MODIFY_LDT_SYSCALL
2307	bool "Enable the LDT (local descriptor table)" if EXPERT
2308	default y
2309	help
2310	  Linux can allow user programs to install a per-process x86
2311	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2312	  call.  This is required to run 16-bit or segmented code such as
2313	  DOSEMU or some Wine programs.  It is also used by some very old
2314	  threading libraries.
2315
2316	  Enabling this feature adds a small amount of overhead to
2317	  context switches and increases the low-level kernel attack
2318	  surface.  Disabling it removes the modify_ldt(2) system call.
2319
2320	  Saying 'N' here may make sense for embedded or server kernels.
2321
2322config STRICT_SIGALTSTACK_SIZE
2323	bool "Enforce strict size checking for sigaltstack"
2324	depends on DYNAMIC_SIGFRAME
2325	help
2326	  For historical reasons MINSIGSTKSZ is a constant which became
2327	  already too small with AVX512 support. Add a mechanism to
2328	  enforce strict checking of the sigaltstack size against the
2329	  real size of the FPU frame. This option enables the check
2330	  by default. It can also be controlled via the kernel command
2331	  line option 'strict_sas_size' independent of this config
2332	  switch. Enabling it might break existing applications which
2333	  allocate a too small sigaltstack but 'work' because they
2334	  never get a signal delivered.
2335
2336	  Say 'N' unless you want to really enforce this check.
2337
2338config CFI_AUTO_DEFAULT
2339	bool "Attempt to use FineIBT by default at boot time"
2340	depends on FINEIBT
2341	depends on !RUST || RUSTC_VERSION >= 108800
2342	default y
2343	help
2344	  Attempt to use FineIBT by default at boot time. If enabled,
2345	  this is the same as booting with "cfi=auto". If disabled,
2346	  this is the same as booting with "cfi=kcfi".
2347
2348source "kernel/livepatch/Kconfig"
2349
2350config X86_BUS_LOCK_DETECT
2351	bool "Split Lock Detect and Bus Lock Detect support"
2352	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2353	default y
2354	help
2355	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2356	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2357
2358endmenu
2359
2360config CC_HAS_NAMED_AS
2361	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2362	depends on CC_IS_GCC
2363
2364#
2365# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2366# are incompatible with named address spaces with GCC < 13.3
2367# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2368#
2369
2370config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2371	def_bool y
2372	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2373	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2374
2375config USE_X86_SEG_SUPPORT
2376	def_bool CC_HAS_NAMED_AS
2377	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2378
2379config CC_HAS_SLS
2380	def_bool $(cc-option,-mharden-sls=all)
2381
2382config CC_HAS_RETURN_THUNK
2383	def_bool $(cc-option,-mfunction-return=thunk-extern)
2384
2385config CC_HAS_ENTRY_PADDING
2386	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2387
2388config CC_HAS_KCFI_ARITY
2389	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2390	depends on CC_IS_CLANG && !RUST
2391
2392config FUNCTION_PADDING_CFI
2393	int
2394	default 59 if FUNCTION_ALIGNMENT_64B
2395	default 27 if FUNCTION_ALIGNMENT_32B
2396	default 11 if FUNCTION_ALIGNMENT_16B
2397	default  3 if FUNCTION_ALIGNMENT_8B
2398	default  0
2399
2400# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2401# except Kconfig can't do arithmetic :/
2402config FUNCTION_PADDING_BYTES
2403	int
2404	default FUNCTION_PADDING_CFI if CFI_CLANG
2405	default FUNCTION_ALIGNMENT
2406
2407config CALL_PADDING
2408	def_bool n
2409	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2410	select FUNCTION_ALIGNMENT_16B
2411
2412config FINEIBT
2413	def_bool y
2414	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2415	select CALL_PADDING
2416
2417config FINEIBT_BHI
2418	def_bool y
2419	depends on FINEIBT && CC_HAS_KCFI_ARITY
2420
2421config HAVE_CALL_THUNKS
2422	def_bool y
2423	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2424
2425config CALL_THUNKS
2426	def_bool n
2427	select CALL_PADDING
2428
2429config PREFIX_SYMBOLS
2430	def_bool y
2431	depends on CALL_PADDING && !CFI_CLANG
2432
2433menuconfig CPU_MITIGATIONS
2434	bool "Mitigations for CPU vulnerabilities"
2435	default y
2436	help
2437	  Say Y here to enable options which enable mitigations for hardware
2438	  vulnerabilities (usually related to speculative execution).
2439	  Mitigations can be disabled or restricted to SMT systems at runtime
2440	  via the "mitigations" kernel parameter.
2441
2442	  If you say N, all mitigations will be disabled.  This CANNOT be
2443	  overridden at runtime.
2444
2445	  Say 'Y', unless you really know what you are doing.
2446
2447if CPU_MITIGATIONS
2448
2449config MITIGATION_PAGE_TABLE_ISOLATION
2450	bool "Remove the kernel mapping in user mode"
2451	default y
2452	depends on (X86_64 || X86_PAE)
2453	help
2454	  This feature reduces the number of hardware side channels by
2455	  ensuring that the majority of kernel addresses are not mapped
2456	  into userspace.
2457
2458	  See Documentation/arch/x86/pti.rst for more details.
2459
2460config MITIGATION_RETPOLINE
2461	bool "Avoid speculative indirect branches in kernel"
2462	select OBJTOOL if HAVE_OBJTOOL
2463	default y
2464	help
2465	  Compile kernel with the retpoline compiler options to guard against
2466	  kernel-to-user data leaks by avoiding speculative indirect
2467	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2468	  support for full protection. The kernel may run slower.
2469
2470config MITIGATION_RETHUNK
2471	bool "Enable return-thunks"
2472	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2473	select OBJTOOL if HAVE_OBJTOOL
2474	default y if X86_64
2475	help
2476	  Compile the kernel with the return-thunks compiler option to guard
2477	  against kernel-to-user data leaks by avoiding return speculation.
2478	  Requires a compiler with -mfunction-return=thunk-extern
2479	  support for full protection. The kernel may run slower.
2480
2481config MITIGATION_UNRET_ENTRY
2482	bool "Enable UNRET on kernel entry"
2483	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2484	default y
2485	help
2486	  Compile the kernel with support for the retbleed=unret mitigation.
2487
2488config MITIGATION_CALL_DEPTH_TRACKING
2489	bool "Mitigate RSB underflow with call depth tracking"
2490	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2491	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2492	select CALL_THUNKS
2493	default y
2494	help
2495	  Compile the kernel with call depth tracking to mitigate the Intel
2496	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2497	  by default and needs to be enabled on the kernel command line via the
2498	  retbleed=stuff option. For non-affected systems the overhead of this
2499	  option is marginal as the call depth tracking is using run-time
2500	  generated call thunks in a compiler generated padding area and call
2501	  patching. This increases text size by ~5%. For non affected systems
2502	  this space is unused. On affected SKL systems this results in a
2503	  significant performance gain over the IBRS mitigation.
2504
2505config CALL_THUNKS_DEBUG
2506	bool "Enable call thunks and call depth tracking debugging"
2507	depends on MITIGATION_CALL_DEPTH_TRACKING
2508	select FUNCTION_ALIGNMENT_32B
2509	default n
2510	help
2511	  Enable call/ret counters for imbalance detection and build in
2512	  a noisy dmesg about callthunks generation and call patching for
2513	  trouble shooting. The debug prints need to be enabled on the
2514	  kernel command line with 'debug-callthunks'.
2515	  Only enable this when you are debugging call thunks as this
2516	  creates a noticeable runtime overhead. If unsure say N.
2517
2518config MITIGATION_IBPB_ENTRY
2519	bool "Enable IBPB on kernel entry"
2520	depends on CPU_SUP_AMD && X86_64
2521	default y
2522	help
2523	  Compile the kernel with support for the retbleed=ibpb and
2524	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2525
2526config MITIGATION_IBRS_ENTRY
2527	bool "Enable IBRS on kernel entry"
2528	depends on CPU_SUP_INTEL && X86_64
2529	default y
2530	help
2531	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2532	  This mitigates both spectre_v2 and retbleed at great cost to
2533	  performance.
2534
2535config MITIGATION_SRSO
2536	bool "Mitigate speculative RAS overflow on AMD"
2537	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2538	default y
2539	help
2540	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2541
2542config MITIGATION_SLS
2543	bool "Mitigate Straight-Line-Speculation"
2544	depends on CC_HAS_SLS && X86_64
2545	select OBJTOOL if HAVE_OBJTOOL
2546	default n
2547	help
2548	  Compile the kernel with straight-line-speculation options to guard
2549	  against straight line speculation. The kernel image might be slightly
2550	  larger.
2551
2552config MITIGATION_GDS
2553	bool "Mitigate Gather Data Sampling"
2554	depends on CPU_SUP_INTEL
2555	default y
2556	help
2557	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2558	  vulnerability which allows unprivileged speculative access to data
2559	  which was previously stored in vector registers. The attacker uses gather
2560	  instructions to infer the stale vector register data.
2561
2562config MITIGATION_RFDS
2563	bool "RFDS Mitigation"
2564	depends on CPU_SUP_INTEL
2565	default y
2566	help
2567	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2568	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2569	  allows unprivileged speculative access to stale data previously
2570	  stored in floating point, vector and integer registers.
2571	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2572
2573config MITIGATION_SPECTRE_BHI
2574	bool "Mitigate Spectre-BHB (Branch History Injection)"
2575	depends on CPU_SUP_INTEL
2576	default y
2577	help
2578	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2579	  where the branch history buffer is poisoned to speculatively steer
2580	  indirect branches.
2581	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2582
2583config MITIGATION_MDS
2584	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2585	depends on CPU_SUP_INTEL
2586	default y
2587	help
2588	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2589	  a hardware vulnerability which allows unprivileged speculative access
2590	  to data which is available in various CPU internal buffers.
2591	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2592
2593config MITIGATION_TAA
2594	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2595	depends on CPU_SUP_INTEL
2596	default y
2597	help
2598	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2599	  vulnerability that allows unprivileged speculative access to data
2600	  which is available in various CPU internal buffers by using
2601	  asynchronous aborts within an Intel TSX transactional region.
2602	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2603
2604config MITIGATION_MMIO_STALE_DATA
2605	bool "Mitigate MMIO Stale Data hardware bug"
2606	depends on CPU_SUP_INTEL
2607	default y
2608	help
2609	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2610	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2611	  vulnerabilities that can expose data. The vulnerabilities require the
2612	  attacker to have access to MMIO.
2613	  See also
2614	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2615
2616config MITIGATION_L1TF
2617	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2618	depends on CPU_SUP_INTEL
2619	default y
2620	help
2621	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2622	  hardware vulnerability which allows unprivileged speculative access to data
2623	  available in the Level 1 Data Cache.
2624	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2625
2626config MITIGATION_RETBLEED
2627	bool "Mitigate RETBleed hardware bug"
2628	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2629	default y
2630	help
2631	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2632	  with Return Instructions) vulnerability.  RETBleed is a speculative
2633	  execution attack which takes advantage of microarchitectural behavior
2634	  in many modern microprocessors, similar to Spectre v2. An
2635	  unprivileged attacker can use these flaws to bypass conventional
2636	  memory security restrictions to gain read access to privileged memory
2637	  that would otherwise be inaccessible.
2638
2639config MITIGATION_SPECTRE_V1
2640	bool "Mitigate SPECTRE V1 hardware bug"
2641	default y
2642	help
2643	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2644	  class of side channel attacks that takes advantage of speculative
2645	  execution that bypasses conditional branch instructions used for
2646	  memory access bounds check.
2647	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2648
2649config MITIGATION_SPECTRE_V2
2650	bool "Mitigate SPECTRE V2 hardware bug"
2651	default y
2652	help
2653	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2654	  V2 is a class of side channel attacks that takes advantage of
2655	  indirect branch predictors inside the processor. In Spectre variant 2
2656	  attacks, the attacker can steer speculative indirect branches in the
2657	  victim to gadget code by poisoning the branch target buffer of a CPU
2658	  used for predicting indirect branch addresses.
2659	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2660
2661config MITIGATION_SRBDS
2662	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2663	depends on CPU_SUP_INTEL
2664	default y
2665	help
2666	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2667	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2668	  Sampling (MDS) techniques to infer values returned from special
2669	  register accesses. An unprivileged user can extract values returned
2670	  from RDRAND and RDSEED executed on another core or sibling thread
2671	  using MDS techniques.
2672	  See also
2673	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2674
2675config MITIGATION_SSB
2676	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2677	default y
2678	help
2679	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2680	  hardware security vulnerability and its exploitation takes advantage
2681	  of speculative execution in a similar way to the Meltdown and Spectre
2682	  security vulnerabilities.
2683
2684config MITIGATION_ITS
2685	bool "Enable Indirect Target Selection mitigation"
2686	depends on CPU_SUP_INTEL && X86_64
2687	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2688	select EXECMEM
2689	default y
2690	help
2691	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2692	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2693	  disabled, mitigation cannot be enabled via cmdline.
2694	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2695
2696config MITIGATION_TSA
2697	bool "Mitigate Transient Scheduler Attacks"
2698	depends on CPU_SUP_AMD
2699	default y
2700	help
2701	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2702	  security vulnerability on AMD CPUs which can lead to forwarding of
2703	  invalid info to subsequent instructions and thus can affect their
2704	  timing and thereby cause a leakage.
2705endif
2706
2707config ARCH_HAS_ADD_PAGES
2708	def_bool y
2709	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2710
2711menu "Power management and ACPI options"
2712
2713config ARCH_HIBERNATION_HEADER
2714	def_bool y
2715	depends on HIBERNATION
2716
2717source "kernel/power/Kconfig"
2718
2719source "drivers/acpi/Kconfig"
2720
2721config X86_APM_BOOT
2722	def_bool y
2723	depends on APM
2724
2725menuconfig APM
2726	tristate "APM (Advanced Power Management) BIOS support"
2727	depends on X86_32 && PM_SLEEP
2728	help
2729	  APM is a BIOS specification for saving power using several different
2730	  techniques. This is mostly useful for battery powered laptops with
2731	  APM compliant BIOSes. If you say Y here, the system time will be
2732	  reset after a RESUME operation, the /proc/apm device will provide
2733	  battery status information, and user-space programs will receive
2734	  notification of APM "events" (e.g. battery status change).
2735
2736	  If you select "Y" here, you can disable actual use of the APM
2737	  BIOS by passing the "apm=off" option to the kernel at boot time.
2738
2739	  Note that the APM support is almost completely disabled for
2740	  machines with more than one CPU.
2741
2742	  In order to use APM, you will need supporting software. For location
2743	  and more information, read <file:Documentation/power/apm-acpi.rst>
2744	  and the Battery Powered Linux mini-HOWTO, available from
2745	  <http://www.tldp.org/docs.html#howto>.
2746
2747	  This driver does not spin down disk drives (see the hdparm(8)
2748	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2749	  VESA-compliant "green" monitors.
2750
2751	  This driver does not support the TI 4000M TravelMate and the ACER
2752	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2753	  desktop machines also don't have compliant BIOSes, and this driver
2754	  may cause those machines to panic during the boot phase.
2755
2756	  Generally, if you don't have a battery in your machine, there isn't
2757	  much point in using this driver and you should say N. If you get
2758	  random kernel OOPSes or reboots that don't seem to be related to
2759	  anything, try disabling/enabling this option (or disabling/enabling
2760	  APM in your BIOS).
2761
2762	  Some other things you should try when experiencing seemingly random,
2763	  "weird" problems:
2764
2765	  1) make sure that you have enough swap space and that it is
2766	  enabled.
2767	  2) pass the "idle=poll" option to the kernel
2768	  3) switch on floating point emulation in the kernel and pass
2769	  the "no387" option to the kernel
2770	  4) pass the "floppy=nodma" option to the kernel
2771	  5) pass the "mem=4M" option to the kernel (thereby disabling
2772	  all but the first 4 MB of RAM)
2773	  6) make sure that the CPU is not over clocked.
2774	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2775	  8) disable the cache from your BIOS settings
2776	  9) install a fan for the video card or exchange video RAM
2777	  10) install a better fan for the CPU
2778	  11) exchange RAM chips
2779	  12) exchange the motherboard.
2780
2781	  To compile this driver as a module, choose M here: the
2782	  module will be called apm.
2783
2784if APM
2785
2786config APM_IGNORE_USER_SUSPEND
2787	bool "Ignore USER SUSPEND"
2788	help
2789	  This option will ignore USER SUSPEND requests. On machines with a
2790	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2791	  series notebooks, it is necessary to say Y because of a BIOS bug.
2792
2793config APM_DO_ENABLE
2794	bool "Enable PM at boot time"
2795	help
2796	  Enable APM features at boot time. From page 36 of the APM BIOS
2797	  specification: "When disabled, the APM BIOS does not automatically
2798	  power manage devices, enter the Standby State, enter the Suspend
2799	  State, or take power saving steps in response to CPU Idle calls."
2800	  This driver will make CPU Idle calls when Linux is idle (unless this
2801	  feature is turned off -- see "Do CPU IDLE calls", below). This
2802	  should always save battery power, but more complicated APM features
2803	  will be dependent on your BIOS implementation. You may need to turn
2804	  this option off if your computer hangs at boot time when using APM
2805	  support, or if it beeps continuously instead of suspending. Turn
2806	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2807	  T400CDT. This is off by default since most machines do fine without
2808	  this feature.
2809
2810config APM_CPU_IDLE
2811	depends on CPU_IDLE
2812	bool "Make CPU Idle calls when idle"
2813	help
2814	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2815	  On some machines, this can activate improved power savings, such as
2816	  a slowed CPU clock rate, when the machine is idle. These idle calls
2817	  are made after the idle loop has run for some length of time (e.g.,
2818	  333 mS). On some machines, this will cause a hang at boot time or
2819	  whenever the CPU becomes idle. (On machines with more than one CPU,
2820	  this option does nothing.)
2821
2822config APM_DISPLAY_BLANK
2823	bool "Enable console blanking using APM"
2824	help
2825	  Enable console blanking using the APM. Some laptops can use this to
2826	  turn off the LCD backlight when the screen blanker of the Linux
2827	  virtual console blanks the screen. Note that this is only used by
2828	  the virtual console screen blanker, and won't turn off the backlight
2829	  when using the X Window system. This also doesn't have anything to
2830	  do with your VESA-compliant power-saving monitor. Further, this
2831	  option doesn't work for all laptops -- it might not turn off your
2832	  backlight at all, or it might print a lot of errors to the console,
2833	  especially if you are using gpm.
2834
2835config APM_ALLOW_INTS
2836	bool "Allow interrupts during APM BIOS calls"
2837	help
2838	  Normally we disable external interrupts while we are making calls to
2839	  the APM BIOS as a measure to lessen the effects of a badly behaving
2840	  BIOS implementation.  The BIOS should reenable interrupts if it
2841	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2842	  many of the newer IBM Thinkpads.  If you experience hangs when you
2843	  suspend, try setting this to Y.  Otherwise, say N.
2844
2845endif # APM
2846
2847source "drivers/cpufreq/Kconfig"
2848
2849source "drivers/cpuidle/Kconfig"
2850
2851source "drivers/idle/Kconfig"
2852
2853endmenu
2854
2855menu "Bus options (PCI etc.)"
2856
2857choice
2858	prompt "PCI access mode"
2859	depends on X86_32 && PCI
2860	default PCI_GOANY
2861	help
2862	  On PCI systems, the BIOS can be used to detect the PCI devices and
2863	  determine their configuration. However, some old PCI motherboards
2864	  have BIOS bugs and may crash if this is done. Also, some embedded
2865	  PCI-based systems don't have any BIOS at all. Linux can also try to
2866	  detect the PCI hardware directly without using the BIOS.
2867
2868	  With this option, you can specify how Linux should detect the
2869	  PCI devices. If you choose "BIOS", the BIOS will be used,
2870	  if you choose "Direct", the BIOS won't be used, and if you
2871	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2872	  If you choose "Any", the kernel will try MMCONFIG, then the
2873	  direct access method and falls back to the BIOS if that doesn't
2874	  work. If unsure, go with the default, which is "Any".
2875
2876config PCI_GOBIOS
2877	bool "BIOS"
2878
2879config PCI_GOMMCONFIG
2880	bool "MMConfig"
2881
2882config PCI_GODIRECT
2883	bool "Direct"
2884
2885config PCI_GOOLPC
2886	bool "OLPC XO-1"
2887	depends on OLPC
2888
2889config PCI_GOANY
2890	bool "Any"
2891
2892endchoice
2893
2894config PCI_BIOS
2895	def_bool y
2896	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2897
2898# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2899config PCI_DIRECT
2900	def_bool y
2901	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2902
2903config PCI_MMCONFIG
2904	bool "Support mmconfig PCI config space access" if X86_64
2905	default y
2906	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2907	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2908	help
2909	  Add support for accessing the PCI configuration space as a memory
2910	  mapped area. It is the recommended method if the system supports
2911	  this (it must have PCI Express and ACPI for it to be available).
2912
2913	  In the unlikely case that enabling this configuration option causes
2914	  problems, the mechanism can be switched off with the 'pci=nommconf'
2915	  command line parameter.
2916
2917	  Say N only if you are sure that your platform does not support this
2918	  access method or you have problems caused by it.
2919
2920	  Say Y otherwise.
2921
2922config PCI_OLPC
2923	def_bool y
2924	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2925
2926config PCI_XEN
2927	def_bool y
2928	depends on PCI && XEN
2929
2930config MMCONF_FAM10H
2931	def_bool y
2932	depends on X86_64 && PCI_MMCONFIG && ACPI
2933
2934config PCI_CNB20LE_QUIRK
2935	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2936	depends on X86_32 && PCI
2937	help
2938	  Read the PCI windows out of the CNB20LE host bridge. This allows
2939	  PCI hotplug to work on systems with the CNB20LE chipset which do
2940	  not have ACPI.
2941
2942	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2943	  most probably only for Pentium III.
2944
2945	  To find out if you have such a chipset, search for a PCI device with
2946	  1166:0009 PCI IDs, for example by executing
2947		lspci -nn | grep '1166:0009'
2948	  The code is inactive if there is none.
2949
2950	  There's no public spec for this chipset, and this functionality
2951	  is known to be incomplete.
2952
2953	  You should say N unless you know you need this.
2954
2955config ISA_BUS
2956	bool "ISA bus support on modern systems" if EXPERT
2957	help
2958	  Expose ISA bus device drivers and options available for selection and
2959	  configuration. Enable this option if your target machine has an ISA
2960	  bus. ISA is an older system, displaced by PCI and newer bus
2961	  architectures -- if your target machine is modern, it probably does
2962	  not have an ISA bus.
2963
2964	  If unsure, say N.
2965
2966# x86_64 have no ISA slots, but can have ISA-style DMA.
2967config ISA_DMA_API
2968	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2969	default y
2970	help
2971	  Enables ISA-style DMA support for devices requiring such controllers.
2972	  If unsure, say Y.
2973
2974if X86_32
2975
2976config ISA
2977	bool "ISA support"
2978	help
2979	  Find out whether you have ISA slots on your motherboard.  ISA is the
2980	  name of a bus system, i.e. the way the CPU talks to the other stuff
2981	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2982	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2983	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2984
2985config SCx200
2986	tristate "NatSemi SCx200 support"
2987	help
2988	  This provides basic support for National Semiconductor's
2989	  (now AMD's) Geode processors.  The driver probes for the
2990	  PCI-IDs of several on-chip devices, so its a good dependency
2991	  for other scx200_* drivers.
2992
2993	  If compiled as a module, the driver is named scx200.
2994
2995config SCx200HR_TIMER
2996	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2997	depends on SCx200
2998	default y
2999	help
3000	  This driver provides a clocksource built upon the on-chip
3001	  27MHz high-resolution timer.  Its also a workaround for
3002	  NSC Geode SC-1100's buggy TSC, which loses time when the
3003	  processor goes idle (as is done by the scheduler).  The
3004	  other workaround is idle=poll boot option.
3005
3006config OLPC
3007	bool "One Laptop Per Child support"
3008	depends on !X86_PAE
3009	select GPIOLIB
3010	select OF
3011	select OF_PROMTREE
3012	select IRQ_DOMAIN
3013	select OLPC_EC
3014	help
3015	  Add support for detecting the unique features of the OLPC
3016	  XO hardware.
3017
3018config OLPC_XO1_PM
3019	bool "OLPC XO-1 Power Management"
3020	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3021	help
3022	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3023
3024config OLPC_XO1_RTC
3025	bool "OLPC XO-1 Real Time Clock"
3026	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3027	help
3028	  Add support for the XO-1 real time clock, which can be used as a
3029	  programmable wakeup source.
3030
3031config OLPC_XO1_SCI
3032	bool "OLPC XO-1 SCI extras"
3033	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3034	depends on INPUT=y
3035	select POWER_SUPPLY
3036	help
3037	  Add support for SCI-based features of the OLPC XO-1 laptop:
3038	   - EC-driven system wakeups
3039	   - Power button
3040	   - Ebook switch
3041	   - Lid switch
3042	   - AC adapter status updates
3043	   - Battery status updates
3044
3045config OLPC_XO15_SCI
3046	bool "OLPC XO-1.5 SCI extras"
3047	depends on OLPC && ACPI
3048	select POWER_SUPPLY
3049	help
3050	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3051	   - EC-driven system wakeups
3052	   - AC adapter status updates
3053	   - Battery status updates
3054
3055config GEODE_COMMON
3056	bool
3057
3058config ALIX
3059	bool "PCEngines ALIX System Support (LED setup)"
3060	select GPIOLIB
3061	select GEODE_COMMON
3062	help
3063	  This option enables system support for the PCEngines ALIX.
3064	  At present this just sets up LEDs for GPIO control on
3065	  ALIX2/3/6 boards.  However, other system specific setup should
3066	  get added here.
3067
3068	  Note: You must still enable the drivers for GPIO and LED support
3069	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3070
3071	  Note: You have to set alix.force=1 for boards with Award BIOS.
3072
3073config NET5501
3074	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3075	select GPIOLIB
3076	select GEODE_COMMON
3077	help
3078	  This option enables system support for the Soekris Engineering net5501.
3079
3080config GEOS
3081	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3082	select GPIOLIB
3083	select GEODE_COMMON
3084	depends on DMI
3085	help
3086	  This option enables system support for the Traverse Technologies GEOS.
3087
3088config TS5500
3089	bool "Technologic Systems TS-5500 platform support"
3090	depends on MELAN
3091	select CHECK_SIGNATURE
3092	select NEW_LEDS
3093	select LEDS_CLASS
3094	help
3095	  This option enables system support for the Technologic Systems TS-5500.
3096
3097endif # X86_32
3098
3099config AMD_NB
3100	def_bool y
3101	depends on AMD_NODE
3102
3103config AMD_NODE
3104	def_bool y
3105	depends on CPU_SUP_AMD && PCI
3106
3107endmenu
3108
3109menu "Binary Emulations"
3110
3111config IA32_EMULATION
3112	bool "IA32 Emulation"
3113	depends on X86_64
3114	select ARCH_WANT_OLD_COMPAT_IPC
3115	select BINFMT_ELF
3116	select COMPAT_OLD_SIGACTION
3117	help
3118	  Include code to run legacy 32-bit programs under a
3119	  64-bit kernel. You should likely turn this on, unless you're
3120	  100% sure that you don't have any 32-bit programs left.
3121
3122config IA32_EMULATION_DEFAULT_DISABLED
3123	bool "IA32 emulation disabled by default"
3124	default n
3125	depends on IA32_EMULATION
3126	help
3127	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3128	  processes and access to 32-bit syscalls. If unsure, leave it to its
3129	  default value.
3130
3131config X86_X32_ABI
3132	bool "x32 ABI for 64-bit mode"
3133	depends on X86_64
3134	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3135	# compressed debug sections to x86_x32 properly:
3136	# https://github.com/ClangBuiltLinux/linux/issues/514
3137	# https://github.com/ClangBuiltLinux/linux/issues/1141
3138	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3139	help
3140	  Include code to run binaries for the x32 native 32-bit ABI
3141	  for 64-bit processors.  An x32 process gets access to the
3142	  full 64-bit register file and wide data path while leaving
3143	  pointers at 32 bits for smaller memory footprint.
3144
3145config COMPAT_32
3146	def_bool y
3147	depends on IA32_EMULATION || X86_32
3148	select HAVE_UID16
3149	select OLD_SIGSUSPEND3
3150
3151config COMPAT
3152	def_bool y
3153	depends on IA32_EMULATION || X86_X32_ABI
3154
3155config COMPAT_FOR_U64_ALIGNMENT
3156	def_bool y
3157	depends on COMPAT
3158
3159endmenu
3160
3161config HAVE_ATOMIC_IOMAP
3162	def_bool y
3163	depends on X86_32
3164
3165source "arch/x86/kvm/Kconfig"
3166
3167source "arch/x86/Kconfig.cpufeatures"
3168
3169source "arch/x86/Kconfig.assembler"
3170