blob: 44c6a82b7ce534c369fad68754cc98bb6f84927f [file] [log] [blame]
Andrew Scullb4b6d4a2019-01-02 15:54:55 +00001# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
6 ---help---
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11 def_bool y
12 depends on !64BIT
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
15 select CLKSRC_I8253
16 select CLONE_BACKWARDS
17 select HAVE_AOUT
18 select HAVE_GENERIC_DMA_COHERENT
19 select MODULES_USE_ELF_REL
20 select OLD_SIGACTION
21
22config X86_64
23 def_bool y
24 depends on 64BIT
25 # Options that are inherently 64-bit kernel only:
26 select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
27 select ARCH_SUPPORTS_INT128
28 select ARCH_USE_CMPXCHG_LOCKREF
29 select HAVE_ARCH_SOFT_DIRTY
30 select MODULES_USE_ELF_RELA
31 select NEED_DMA_MAP_STATE
32 select SWIOTLB
33 select X86_DEV_DMA_OPS
34 select ARCH_HAS_SYSCALL_WRAPPER
35
36#
37# Arch settings
38#
39# ( Note that options that are marked 'if X86_64' could in principle be
40# ported to 32-bit as well. )
41#
42config X86
43 def_bool y
44 #
45 # Note: keep this list sorted alphabetically
46 #
47 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
48 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
49 select ANON_INODES
50 select ARCH_CLOCKSOURCE_DATA
51 select ARCH_DISCARD_MEMBLOCK
52 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
53 select ARCH_HAS_DEBUG_VIRTUAL
54 select ARCH_HAS_DEVMEM_IS_ALLOWED
55 select ARCH_HAS_ELF_RANDOMIZE
56 select ARCH_HAS_FAST_MULTIPLIER
57 select ARCH_HAS_FILTER_PGPROT
58 select ARCH_HAS_FORTIFY_SOURCE
59 select ARCH_HAS_GCOV_PROFILE_ALL
60 select ARCH_HAS_KCOV if X86_64
61 select ARCH_HAS_MEMBARRIER_SYNC_CORE
62 select ARCH_HAS_PMEM_API if X86_64
63 select ARCH_HAS_PTE_SPECIAL
64 select ARCH_HAS_REFCOUNT
65 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
66 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
67 select ARCH_HAS_SET_MEMORY
68 select ARCH_HAS_SG_CHAIN
69 select ARCH_HAS_STRICT_KERNEL_RWX
70 select ARCH_HAS_STRICT_MODULE_RWX
71 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
72 select ARCH_HAS_UBSAN_SANITIZE_ALL
73 select ARCH_HAS_ZONE_DEVICE if X86_64
74 select ARCH_HAVE_NMI_SAFE_CMPXCHG
75 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
76 select ARCH_MIGHT_HAVE_PC_PARPORT
77 select ARCH_MIGHT_HAVE_PC_SERIO
78 select ARCH_SUPPORTS_ACPI
79 select ARCH_SUPPORTS_ATOMIC_RMW
80 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
81 select ARCH_USE_BUILTIN_BSWAP
82 select ARCH_USE_QUEUED_RWLOCKS
83 select ARCH_USE_QUEUED_SPINLOCKS
84 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
85 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
86 select ARCH_WANTS_THP_SWAP if X86_64
87 select BUILDTIME_EXTABLE_SORT
88 select CLKEVT_I8253
89 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
90 select CLOCKSOURCE_WATCHDOG
91 select DCACHE_WORD_ACCESS
92 select DMA_DIRECT_OPS
93 select EDAC_ATOMIC_SCRUB
94 select EDAC_SUPPORT
95 select GENERIC_CLOCKEVENTS
96 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
97 select GENERIC_CLOCKEVENTS_MIN_ADJUST
98 select GENERIC_CMOS_UPDATE
99 select GENERIC_CPU_AUTOPROBE
100 select GENERIC_CPU_VULNERABILITIES
101 select GENERIC_EARLY_IOREMAP
102 select GENERIC_FIND_FIRST_BIT
103 select GENERIC_IOMAP
104 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
105 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
106 select GENERIC_IRQ_MIGRATION if SMP
107 select GENERIC_IRQ_PROBE
108 select GENERIC_IRQ_RESERVATION_MODE
109 select GENERIC_IRQ_SHOW
110 select GENERIC_PENDING_IRQ if SMP
111 select GENERIC_SMP_IDLE_THREAD
112 select GENERIC_STRNCPY_FROM_USER
113 select GENERIC_STRNLEN_USER
114 select GENERIC_TIME_VSYSCALL
115 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
116 select HAVE_ACPI_APEI if ACPI
117 select HAVE_ACPI_APEI_NMI if ACPI
118 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
119 select HAVE_ARCH_AUDITSYSCALL
120 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
121 select HAVE_ARCH_JUMP_LABEL
122 select HAVE_ARCH_KASAN if X86_64
123 select HAVE_ARCH_KGDB
124 select HAVE_ARCH_MMAP_RND_BITS if MMU
125 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
126 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
127 select HAVE_ARCH_PREL32_RELOCATIONS
128 select HAVE_ARCH_SECCOMP_FILTER
129 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
130 select HAVE_ARCH_TRACEHOOK
131 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
132 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
133 select HAVE_ARCH_VMAP_STACK if X86_64
134 select HAVE_ARCH_WITHIN_STACK_FRAMES
135 select HAVE_CMPXCHG_DOUBLE
136 select HAVE_CMPXCHG_LOCAL
137 select HAVE_CONTEXT_TRACKING if X86_64
138 select HAVE_COPY_THREAD_TLS
139 select HAVE_C_RECORDMCOUNT
140 select HAVE_DEBUG_KMEMLEAK
141 select HAVE_DEBUG_STACKOVERFLOW
142 select HAVE_DMA_CONTIGUOUS
143 select HAVE_DYNAMIC_FTRACE
144 select HAVE_DYNAMIC_FTRACE_WITH_REGS
145 select HAVE_EBPF_JIT
146 select HAVE_EFFICIENT_UNALIGNED_ACCESS
147 select HAVE_EXIT_THREAD
148 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
149 select HAVE_FTRACE_MCOUNT_RECORD
150 select HAVE_FUNCTION_GRAPH_TRACER
151 select HAVE_FUNCTION_TRACER
152 select HAVE_GCC_PLUGINS
153 select HAVE_HW_BREAKPOINT
154 select HAVE_IDE
155 select HAVE_IOREMAP_PROT
156 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
157 select HAVE_IRQ_TIME_ACCOUNTING
158 select HAVE_KERNEL_BZIP2
159 select HAVE_KERNEL_GZIP
160 select HAVE_KERNEL_LZ4
161 select HAVE_KERNEL_LZMA
162 select HAVE_KERNEL_LZO
163 select HAVE_KERNEL_XZ
164 select HAVE_KPROBES
165 select HAVE_KPROBES_ON_FTRACE
166 select HAVE_FUNCTION_ERROR_INJECTION
167 select HAVE_KRETPROBES
168 select HAVE_KVM
169 select HAVE_LIVEPATCH if X86_64
170 select HAVE_MEMBLOCK
171 select HAVE_MEMBLOCK_NODE_MAP
172 select HAVE_MIXED_BREAKPOINTS_REGS
173 select HAVE_MOD_ARCH_SPECIFIC
174 select HAVE_NMI
175 select HAVE_OPROFILE
176 select HAVE_OPTPROBES
177 select HAVE_PCSPKR_PLATFORM
178 select HAVE_PERF_EVENTS
179 select HAVE_PERF_EVENTS_NMI
180 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
181 select HAVE_PERF_REGS
182 select HAVE_PERF_USER_STACK_DUMP
183 select HAVE_RCU_TABLE_FREE if PARAVIRT
184 select HAVE_RCU_TABLE_INVALIDATE if HAVE_RCU_TABLE_FREE
185 select HAVE_REGS_AND_STACK_ACCESS_API
186 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
187 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
188 select HAVE_STACK_VALIDATION if X86_64
189 select HAVE_RSEQ
190 select HAVE_SYSCALL_TRACEPOINTS
191 select HAVE_UNSTABLE_SCHED_CLOCK
192 select HAVE_USER_RETURN_NOTIFIER
193 select HOTPLUG_SMT if SMP
194 select IRQ_FORCED_THREADING
195 select NEED_SG_DMA_LENGTH
196 select PCI_LOCKLESS_CONFIG
197 select PERF_EVENTS
198 select RTC_LIB
199 select RTC_MC146818_LIB
200 select SPARSE_IRQ
201 select SRCU
202 select SYSCTL_EXCEPTION_TRACE
203 select THREAD_INFO_IN_TASK
204 select USER_STACKTRACE_SUPPORT
205 select VIRT_TO_BUS
206 select X86_FEATURE_NAMES if PROC_FS
207
208config INSTRUCTION_DECODER
209 def_bool y
210 depends on KPROBES || PERF_EVENTS || UPROBES
211
212config OUTPUT_FORMAT
213 string
214 default "elf32-i386" if X86_32
215 default "elf64-x86-64" if X86_64
216
217config ARCH_DEFCONFIG
218 string
219 default "arch/x86/configs/i386_defconfig" if X86_32
220 default "arch/x86/configs/x86_64_defconfig" if X86_64
221
222config LOCKDEP_SUPPORT
223 def_bool y
224
225config STACKTRACE_SUPPORT
226 def_bool y
227
228config MMU
229 def_bool y
230
231config ARCH_MMAP_RND_BITS_MIN
232 default 28 if 64BIT
233 default 8
234
235config ARCH_MMAP_RND_BITS_MAX
236 default 32 if 64BIT
237 default 16
238
239config ARCH_MMAP_RND_COMPAT_BITS_MIN
240 default 8
241
242config ARCH_MMAP_RND_COMPAT_BITS_MAX
243 default 16
244
245config SBUS
246 bool
247
248config GENERIC_ISA_DMA
249 def_bool y
250 depends on ISA_DMA_API
251
252config GENERIC_BUG
253 def_bool y
254 depends on BUG
255 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
256
257config GENERIC_BUG_RELATIVE_POINTERS
258 bool
259
260config GENERIC_HWEIGHT
261 def_bool y
262
263config ARCH_MAY_HAVE_PC_FDC
264 def_bool y
265 depends on ISA_DMA_API
266
267config RWSEM_XCHGADD_ALGORITHM
268 def_bool y
269
270config GENERIC_CALIBRATE_DELAY
271 def_bool y
272
273config ARCH_HAS_CPU_RELAX
274 def_bool y
275
276config ARCH_HAS_CACHE_LINE_SIZE
277 def_bool y
278
279config ARCH_HAS_FILTER_PGPROT
280 def_bool y
281
282config HAVE_SETUP_PER_CPU_AREA
283 def_bool y
284
285config NEED_PER_CPU_EMBED_FIRST_CHUNK
286 def_bool y
287
288config NEED_PER_CPU_PAGE_FIRST_CHUNK
289 def_bool y
290
291config ARCH_HIBERNATION_POSSIBLE
292 def_bool y
293
294config ARCH_SUSPEND_POSSIBLE
295 def_bool y
296
297config ARCH_WANT_HUGE_PMD_SHARE
298 def_bool y
299
300config ARCH_WANT_GENERAL_HUGETLB
301 def_bool y
302
303config ZONE_DMA32
304 def_bool y if X86_64
305
306config AUDIT_ARCH
307 def_bool y if X86_64
308
309config ARCH_SUPPORTS_OPTIMIZED_INLINING
310 def_bool y
311
312config ARCH_SUPPORTS_DEBUG_PAGEALLOC
313 def_bool y
314
315config KASAN_SHADOW_OFFSET
316 hex
317 depends on KASAN
318 default 0xdffffc0000000000
319
320config HAVE_INTEL_TXT
321 def_bool y
322 depends on INTEL_IOMMU && ACPI
323
324config X86_32_SMP
325 def_bool y
326 depends on X86_32 && SMP
327
328config X86_64_SMP
329 def_bool y
330 depends on X86_64 && SMP
331
332config X86_32_LAZY_GS
333 def_bool y
334 depends on X86_32 && !STACKPROTECTOR
335
336config ARCH_SUPPORTS_UPROBES
337 def_bool y
338
339config FIX_EARLYCON_MEM
340 def_bool y
341
342config DYNAMIC_PHYSICAL_MASK
343 bool
344
345config PGTABLE_LEVELS
346 int
347 default 5 if X86_5LEVEL
348 default 4 if X86_64
349 default 3 if X86_PAE
350 default 2
351
352config CC_HAS_SANE_STACKPROTECTOR
353 bool
354 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
355 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
356 help
357 We have to make sure stack protector is unconditionally disabled if
358 the compiler produces broken code.
359
360menu "Processor type and features"
361
362config ZONE_DMA
363 bool "DMA memory allocation support" if EXPERT
364 default y
365 help
366 DMA memory allocation support allows devices with less than 32-bit
367 addressing to allocate within the first 16MB of address space.
368 Disable if no such devices will be used.
369
370 If unsure, say Y.
371
372config SMP
373 bool "Symmetric multi-processing support"
374 ---help---
375 This enables support for systems with more than one CPU. If you have
376 a system with only one CPU, say N. If you have a system with more
377 than one CPU, say Y.
378
379 If you say N here, the kernel will run on uni- and multiprocessor
380 machines, but will use only one CPU of a multiprocessor machine. If
381 you say Y here, the kernel will run on many, but not all,
382 uniprocessor machines. On a uniprocessor machine, the kernel
383 will run faster if you say N here.
384
385 Note that if you say Y here and choose architecture "586" or
386 "Pentium" under "Processor family", the kernel will not work on 486
387 architectures. Similarly, multiprocessor kernels for the "PPro"
388 architecture may not work on all Pentium based boards.
389
390 People using multiprocessor machines who say Y here should also say
391 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
392 Management" code will be disabled if you say Y here.
393
394 See also <file:Documentation/x86/i386/IO-APIC.txt>,
395 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
396 <http://www.tldp.org/docs.html#howto>.
397
398 If you don't know what to do here, say N.
399
400config X86_FEATURE_NAMES
401 bool "Processor feature human-readable names" if EMBEDDED
402 default y
403 ---help---
404 This option compiles in a table of x86 feature bits and corresponding
405 names. This is required to support /proc/cpuinfo and a few kernel
406 messages. You can disable this to save space, at the expense of
407 making those few kernel messages show numeric feature bits instead.
408
409 If in doubt, say Y.
410
411config X86_X2APIC
412 bool "Support x2apic"
413 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
414 ---help---
415 This enables x2apic support on CPUs that have this feature.
416
417 This allows 32-bit apic IDs (so it can support very large systems),
418 and accesses the local apic via MSRs not via mmio.
419
420 If you don't know what to do here, say N.
421
422config X86_MPPARSE
423 bool "Enable MPS table" if ACPI || SFI
424 default y
425 depends on X86_LOCAL_APIC
426 ---help---
427 For old smp systems that do not have proper acpi support. Newer systems
428 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
429
430config GOLDFISH
431 def_bool y
432 depends on X86_GOLDFISH
433
434config RETPOLINE
435 bool "Avoid speculative indirect branches in kernel"
436 default y
437 select STACK_VALIDATION if HAVE_STACK_VALIDATION
438 help
439 Compile kernel with the retpoline compiler options to guard against
440 kernel-to-user data leaks by avoiding speculative indirect
441 branches. Requires a compiler with -mindirect-branch=thunk-extern
442 support for full protection. The kernel may run slower.
443
444config INTEL_RDT
445 bool "Intel Resource Director Technology support"
446 default n
447 depends on X86 && CPU_SUP_INTEL
448 select KERNFS
449 help
450 Select to enable resource allocation and monitoring which are
451 sub-features of Intel Resource Director Technology(RDT). More
452 information about RDT can be found in the Intel x86
453 Architecture Software Developer Manual.
454
455 Say N if unsure.
456
457if X86_32
458config X86_BIGSMP
459 bool "Support for big SMP systems with more than 8 CPUs"
460 depends on SMP
461 ---help---
462 This option is needed for the systems that have more than 8 CPUs
463
464config X86_EXTENDED_PLATFORM
465 bool "Support for extended (non-PC) x86 platforms"
466 default y
467 ---help---
468 If you disable this option then the kernel will only support
469 standard PC platforms. (which covers the vast majority of
470 systems out there.)
471
472 If you enable this option then you'll be able to select support
473 for the following (non-PC) 32 bit x86 platforms:
474 Goldfish (Android emulator)
475 AMD Elan
476 RDC R-321x SoC
477 SGI 320/540 (Visual Workstation)
478 STA2X11-based (e.g. Northville)
479 Moorestown MID devices
480
481 If you have one of these systems, or if you want to build a
482 generic distribution kernel, say Y here - otherwise say N.
483endif
484
485if X86_64
486config X86_EXTENDED_PLATFORM
487 bool "Support for extended (non-PC) x86 platforms"
488 default y
489 ---help---
490 If you disable this option then the kernel will only support
491 standard PC platforms. (which covers the vast majority of
492 systems out there.)
493
494 If you enable this option then you'll be able to select support
495 for the following (non-PC) 64 bit x86 platforms:
496 Numascale NumaChip
497 ScaleMP vSMP
498 SGI Ultraviolet
499
500 If you have one of these systems, or if you want to build a
501 generic distribution kernel, say Y here - otherwise say N.
502endif
503# This is an alphabetically sorted list of 64 bit extended platforms
504# Please maintain the alphabetic order if and when there are additions
505config X86_NUMACHIP
506 bool "Numascale NumaChip"
507 depends on X86_64
508 depends on X86_EXTENDED_PLATFORM
509 depends on NUMA
510 depends on SMP
511 depends on X86_X2APIC
512 depends on PCI_MMCONFIG
513 ---help---
514 Adds support for Numascale NumaChip large-SMP systems. Needed to
515 enable more than ~168 cores.
516 If you don't have one of these, you should say N here.
517
518config X86_VSMP
519 bool "ScaleMP vSMP"
520 select HYPERVISOR_GUEST
521 select PARAVIRT
522 depends on X86_64 && PCI
523 depends on X86_EXTENDED_PLATFORM
524 depends on SMP
525 ---help---
526 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
527 supposed to run on these EM64T-based machines. Only choose this option
528 if you have one of these machines.
529
530config X86_UV
531 bool "SGI Ultraviolet"
532 depends on X86_64
533 depends on X86_EXTENDED_PLATFORM
534 depends on NUMA
535 depends on EFI
536 depends on X86_X2APIC
537 depends on PCI
538 ---help---
539 This option is needed in order to support SGI Ultraviolet systems.
540 If you don't have one of these, you should say N here.
541
542# Following is an alphabetically sorted list of 32 bit extended platforms
543# Please maintain the alphabetic order if and when there are additions
544
545config X86_GOLDFISH
546 bool "Goldfish (Virtual Platform)"
547 depends on X86_EXTENDED_PLATFORM
548 ---help---
549 Enable support for the Goldfish virtual platform used primarily
550 for Android development. Unless you are building for the Android
551 Goldfish emulator say N here.
552
553config X86_INTEL_CE
554 bool "CE4100 TV platform"
555 depends on PCI
556 depends on PCI_GODIRECT
557 depends on X86_IO_APIC
558 depends on X86_32
559 depends on X86_EXTENDED_PLATFORM
560 select X86_REBOOTFIXUPS
561 select OF
562 select OF_EARLY_FLATTREE
563 ---help---
564 Select for the Intel CE media processor (CE4100) SOC.
565 This option compiles in support for the CE4100 SOC for settop
566 boxes and media devices.
567
568config X86_INTEL_MID
569 bool "Intel MID platform support"
570 depends on X86_EXTENDED_PLATFORM
571 depends on X86_PLATFORM_DEVICES
572 depends on PCI
573 depends on X86_64 || (PCI_GOANY && X86_32)
574 depends on X86_IO_APIC
575 select SFI
576 select I2C
577 select DW_APB_TIMER
578 select APB_TIMER
579 select INTEL_SCU_IPC
580 select MFD_INTEL_MSIC
581 ---help---
582 Select to build a kernel capable of supporting Intel MID (Mobile
583 Internet Device) platform systems which do not have the PCI legacy
584 interfaces. If you are building for a PC class system say N here.
585
586 Intel MID platforms are based on an Intel processor and chipset which
587 consume less power than most of the x86 derivatives.
588
589config X86_INTEL_QUARK
590 bool "Intel Quark platform support"
591 depends on X86_32
592 depends on X86_EXTENDED_PLATFORM
593 depends on X86_PLATFORM_DEVICES
594 depends on X86_TSC
595 depends on PCI
596 depends on PCI_GOANY
597 depends on X86_IO_APIC
598 select IOSF_MBI
599 select INTEL_IMR
600 select COMMON_CLK
601 ---help---
602 Select to include support for Quark X1000 SoC.
603 Say Y here if you have a Quark based system such as the Arduino
604 compatible Intel Galileo.
605
606config X86_INTEL_LPSS
607 bool "Intel Low Power Subsystem Support"
608 depends on X86 && ACPI
609 select COMMON_CLK
610 select PINCTRL
611 select IOSF_MBI
612 ---help---
613 Select to build support for Intel Low Power Subsystem such as
614 found on Intel Lynxpoint PCH. Selecting this option enables
615 things like clock tree (common clock framework) and pincontrol
616 which are needed by the LPSS peripheral drivers.
617
618config X86_AMD_PLATFORM_DEVICE
619 bool "AMD ACPI2Platform devices support"
620 depends on ACPI
621 select COMMON_CLK
622 select PINCTRL
623 ---help---
624 Select to interpret AMD specific ACPI device to platform device
625 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
626 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
627 implemented under PINCTRL subsystem.
628
629config IOSF_MBI
630 tristate "Intel SoC IOSF Sideband support for SoC platforms"
631 depends on PCI
632 ---help---
633 This option enables sideband register access support for Intel SoC
634 platforms. On these platforms the IOSF sideband is used in lieu of
635 MSR's for some register accesses, mostly but not limited to thermal
636 and power. Drivers may query the availability of this device to
637 determine if they need the sideband in order to work on these
638 platforms. The sideband is available on the following SoC products.
639 This list is not meant to be exclusive.
640 - BayTrail
641 - Braswell
642 - Quark
643
644 You should say Y if you are running a kernel on one of these SoC's.
645
646config IOSF_MBI_DEBUG
647 bool "Enable IOSF sideband access through debugfs"
648 depends on IOSF_MBI && DEBUG_FS
649 ---help---
650 Select this option to expose the IOSF sideband access registers (MCR,
651 MDR, MCRX) through debugfs to write and read register information from
652 different units on the SoC. This is most useful for obtaining device
653 state information for debug and analysis. As this is a general access
654 mechanism, users of this option would have specific knowledge of the
655 device they want to access.
656
657 If you don't require the option or are in doubt, say N.
658
659config X86_RDC321X
660 bool "RDC R-321x SoC"
661 depends on X86_32
662 depends on X86_EXTENDED_PLATFORM
663 select M486
664 select X86_REBOOTFIXUPS
665 ---help---
666 This option is needed for RDC R-321x system-on-chip, also known
667 as R-8610-(G).
668 If you don't have one of these chips, you should say N here.
669
670config X86_32_NON_STANDARD
671 bool "Support non-standard 32-bit SMP architectures"
672 depends on X86_32 && SMP
673 depends on X86_EXTENDED_PLATFORM
674 ---help---
675 This option compiles in the bigsmp and STA2X11 default
676 subarchitectures. It is intended for a generic binary
677 kernel. If you select them all, kernel will probe it one by
678 one and will fallback to default.
679
680# Alphabetically sorted list of Non standard 32 bit platforms
681
682config X86_SUPPORTS_MEMORY_FAILURE
683 def_bool y
684 # MCE code calls memory_failure():
685 depends on X86_MCE
686 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
687 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
688 depends on X86_64 || !SPARSEMEM
689 select ARCH_SUPPORTS_MEMORY_FAILURE
690
691config STA2X11
692 bool "STA2X11 Companion Chip Support"
693 depends on X86_32_NON_STANDARD && PCI
694 select ARCH_HAS_PHYS_TO_DMA
695 select X86_DEV_DMA_OPS
696 select X86_DMA_REMAP
697 select SWIOTLB
698 select MFD_STA2X11
699 select GPIOLIB
700 default n
701 ---help---
702 This adds support for boards based on the STA2X11 IO-Hub,
703 a.k.a. "ConneXt". The chip is used in place of the standard
704 PC chipset, so all "standard" peripherals are missing. If this
705 option is selected the kernel will still be able to boot on
706 standard PC machines.
707
708config X86_32_IRIS
709 tristate "Eurobraille/Iris poweroff module"
710 depends on X86_32
711 ---help---
712 The Iris machines from EuroBraille do not have APM or ACPI support
713 to shut themselves down properly. A special I/O sequence is
714 needed to do so, which is what this module does at
715 kernel shutdown.
716
717 This is only for Iris machines from EuroBraille.
718
719 If unused, say N.
720
721config SCHED_OMIT_FRAME_POINTER
722 def_bool y
723 prompt "Single-depth WCHAN output"
724 depends on X86
725 ---help---
726 Calculate simpler /proc/<PID>/wchan values. If this option
727 is disabled then wchan values will recurse back to the
728 caller function. This provides more accurate wchan values,
729 at the expense of slightly more scheduling overhead.
730
731 If in doubt, say "Y".
732
733menuconfig HYPERVISOR_GUEST
734 bool "Linux guest support"
735 ---help---
736 Say Y here to enable options for running Linux under various hyper-
737 visors. This option enables basic hypervisor detection and platform
738 setup.
739
740 If you say N, all options in this submenu will be skipped and
741 disabled, and Linux guest support won't be built in.
742
743if HYPERVISOR_GUEST
744
745config PARAVIRT
746 bool "Enable paravirtualization code"
747 ---help---
748 This changes the kernel so it can modify itself when it is run
749 under a hypervisor, potentially improving performance significantly
750 over full virtualization. However, when run without a hypervisor
751 the kernel is theoretically slower and slightly larger.
752
753config PARAVIRT_DEBUG
754 bool "paravirt-ops debugging"
755 depends on PARAVIRT && DEBUG_KERNEL
756 ---help---
757 Enable to debug paravirt_ops internals. Specifically, BUG if
758 a paravirt_op is missing when it is called.
759
760config PARAVIRT_SPINLOCKS
761 bool "Paravirtualization layer for spinlocks"
762 depends on PARAVIRT && SMP
763 ---help---
764 Paravirtualized spinlocks allow a pvops backend to replace the
765 spinlock implementation with something virtualization-friendly
766 (for example, block the virtual CPU rather than spinning).
767
768 It has a minimal impact on native kernels and gives a nice performance
769 benefit on paravirtualized KVM / Xen kernels.
770
771 If you are unsure how to answer this question, answer Y.
772
773config QUEUED_LOCK_STAT
774 bool "Paravirt queued spinlock statistics"
775 depends on PARAVIRT_SPINLOCKS && DEBUG_FS
776 ---help---
777 Enable the collection of statistical data on the slowpath
778 behavior of paravirtualized queued spinlocks and report
779 them on debugfs.
780
781source "arch/x86/xen/Kconfig"
782
783config KVM_GUEST
784 bool "KVM Guest support (including kvmclock)"
785 depends on PARAVIRT
786 select PARAVIRT_CLOCK
787 default y
788 ---help---
789 This option enables various optimizations for running under the KVM
790 hypervisor. It includes a paravirtualized clock, so that instead
791 of relying on a PIT (or probably other) emulation by the
792 underlying device model, the host provides the guest with
793 timing infrastructure such as time of day, and system time
794
795config KVM_DEBUG_FS
796 bool "Enable debug information for KVM Guests in debugfs"
797 depends on KVM_GUEST && DEBUG_FS
798 default n
799 ---help---
800 This option enables collection of various statistics for KVM guest.
801 Statistics are displayed in debugfs filesystem. Enabling this option
802 may incur significant overhead.
803
804config PARAVIRT_TIME_ACCOUNTING
805 bool "Paravirtual steal time accounting"
806 depends on PARAVIRT
807 default n
808 ---help---
809 Select this option to enable fine granularity task steal time
810 accounting. Time spent executing other tasks in parallel with
811 the current vCPU is discounted from the vCPU power. To account for
812 that, there can be a small performance impact.
813
814 If in doubt, say N here.
815
816config PARAVIRT_CLOCK
817 bool
818
819config JAILHOUSE_GUEST
820 bool "Jailhouse non-root cell support"
821 depends on X86_64 && PCI
822 select X86_PM_TIMER
823 ---help---
824 This option allows to run Linux as guest in a Jailhouse non-root
825 cell. You can leave this option disabled if you only want to start
826 Jailhouse and run Linux afterwards in the root cell.
827
828endif #HYPERVISOR_GUEST
829
830config NO_BOOTMEM
831 def_bool y
832
833source "arch/x86/Kconfig.cpu"
834
835config HPET_TIMER
836 def_bool X86_64
837 prompt "HPET Timer Support" if X86_32
838 ---help---
839 Use the IA-PC HPET (High Precision Event Timer) to manage
840 time in preference to the PIT and RTC, if a HPET is
841 present.
842 HPET is the next generation timer replacing legacy 8254s.
843 The HPET provides a stable time base on SMP
844 systems, unlike the TSC, but it is more expensive to access,
845 as it is off-chip. The interface used is documented
846 in the HPET spec, revision 1.
847
848 You can safely choose Y here. However, HPET will only be
849 activated if the platform and the BIOS support this feature.
850 Otherwise the 8254 will be used for timing services.
851
852 Choose N to continue using the legacy 8254 timer.
853
854config HPET_EMULATE_RTC
855 def_bool y
856 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
857
858config APB_TIMER
859 def_bool y if X86_INTEL_MID
860 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
861 select DW_APB_TIMER
862 depends on X86_INTEL_MID && SFI
863 help
864 APB timer is the replacement for 8254, HPET on X86 MID platforms.
865 The APBT provides a stable time base on SMP
866 systems, unlike the TSC, but it is more expensive to access,
867 as it is off-chip. APB timers are always running regardless of CPU
868 C states, they are used as per CPU clockevent device when possible.
869
870# Mark as expert because too many people got it wrong.
871# The code disables itself when not needed.
872config DMI
873 default y
874 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
875 bool "Enable DMI scanning" if EXPERT
876 ---help---
877 Enabled scanning of DMI to identify machine quirks. Say Y
878 here unless you have verified that your setup is not
879 affected by entries in the DMI blacklist. Required by PNP
880 BIOS code.
881
882config GART_IOMMU
883 bool "Old AMD GART IOMMU support"
884 select IOMMU_HELPER
885 select SWIOTLB
886 depends on X86_64 && PCI && AMD_NB
887 ---help---
888 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
889 GART based hardware IOMMUs.
890
891 The GART supports full DMA access for devices with 32-bit access
892 limitations, on systems with more than 3 GB. This is usually needed
893 for USB, sound, many IDE/SATA chipsets and some other devices.
894
895 Newer systems typically have a modern AMD IOMMU, supported via
896 the CONFIG_AMD_IOMMU=y config option.
897
898 In normal configurations this driver is only active when needed:
899 there's more than 3 GB of memory and the system contains a
900 32-bit limited device.
901
902 If unsure, say Y.
903
904config CALGARY_IOMMU
905 bool "IBM Calgary IOMMU support"
906 select IOMMU_HELPER
907 select SWIOTLB
908 depends on X86_64 && PCI
909 ---help---
910 Support for hardware IOMMUs in IBM's xSeries x366 and x460
911 systems. Needed to run systems with more than 3GB of memory
912 properly with 32-bit PCI devices that do not support DAC
913 (Double Address Cycle). Calgary also supports bus level
914 isolation, where all DMAs pass through the IOMMU. This
915 prevents them from going anywhere except their intended
916 destination. This catches hard-to-find kernel bugs and
917 mis-behaving drivers and devices that do not use the DMA-API
918 properly to set up their DMA buffers. The IOMMU can be
919 turned off at boot time with the iommu=off parameter.
920 Normally the kernel will make the right choice by itself.
921 If unsure, say Y.
922
923config CALGARY_IOMMU_ENABLED_BY_DEFAULT
924 def_bool y
925 prompt "Should Calgary be enabled by default?"
926 depends on CALGARY_IOMMU
927 ---help---
928 Should Calgary be enabled by default? if you choose 'y', Calgary
929 will be used (if it exists). If you choose 'n', Calgary will not be
930 used even if it exists. If you choose 'n' and would like to use
931 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
932 If unsure, say Y.
933
934config MAXSMP
935 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
936 depends on X86_64 && SMP && DEBUG_KERNEL
937 select CPUMASK_OFFSTACK
938 ---help---
939 Enable maximum number of CPUS and NUMA Nodes for this architecture.
940 If unsure, say N.
941
942#
943# The maximum number of CPUs supported:
944#
945# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
946# and which can be configured interactively in the
947# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
948#
949# The ranges are different on 32-bit and 64-bit kernels, depending on
950# hardware capabilities and scalability features of the kernel.
951#
952# ( If MAXSMP is enabled we just use the highest possible value and disable
953# interactive configuration. )
954#
955
956config NR_CPUS_RANGE_BEGIN
957 int
958 default NR_CPUS_RANGE_END if MAXSMP
959 default 1 if !SMP
960 default 2
961
962config NR_CPUS_RANGE_END
963 int
964 depends on X86_32
965 default 64 if SMP && X86_BIGSMP
966 default 8 if SMP && !X86_BIGSMP
967 default 1 if !SMP
968
969config NR_CPUS_RANGE_END
970 int
971 depends on X86_64
972 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK)
973 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
974 default 1 if !SMP
975
976config NR_CPUS_DEFAULT
977 int
978 depends on X86_32
979 default 32 if X86_BIGSMP
980 default 8 if SMP
981 default 1 if !SMP
982
983config NR_CPUS_DEFAULT
984 int
985 depends on X86_64
986 default 8192 if MAXSMP
987 default 64 if SMP
988 default 1 if !SMP
989
990config NR_CPUS
991 int "Maximum number of CPUs" if SMP && !MAXSMP
992 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
993 default NR_CPUS_DEFAULT
994 ---help---
995 This allows you to specify the maximum number of CPUs which this
996 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
997 supported value is 8192, otherwise the maximum value is 512. The
998 minimum value which makes sense is 2.
999
1000 This is purely to save memory: each supported CPU adds about 8KB
1001 to the kernel image.
1002
1003config SCHED_SMT
1004 def_bool y if SMP
1005
1006config SCHED_MC
1007 def_bool y
1008 prompt "Multi-core scheduler support"
1009 depends on SMP
1010 ---help---
1011 Multi-core scheduler support improves the CPU scheduler's decision
1012 making when dealing with multi-core CPU chips at a cost of slightly
1013 increased overhead in some places. If unsure say N here.
1014
1015config SCHED_MC_PRIO
1016 bool "CPU core priorities scheduler support"
1017 depends on SCHED_MC && CPU_SUP_INTEL
1018 select X86_INTEL_PSTATE
1019 select CPU_FREQ
1020 default y
1021 ---help---
1022 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1023 core ordering determined at manufacturing time, which allows
1024 certain cores to reach higher turbo frequencies (when running
1025 single threaded workloads) than others.
1026
1027 Enabling this kernel feature teaches the scheduler about
1028 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1029 scheduler's CPU selection logic accordingly, so that higher
1030 overall system performance can be achieved.
1031
1032 This feature will have no effect on CPUs without this feature.
1033
1034 If unsure say Y here.
1035
1036config UP_LATE_INIT
1037 def_bool y
1038 depends on !SMP && X86_LOCAL_APIC
1039
1040config X86_UP_APIC
1041 bool "Local APIC support on uniprocessors" if !PCI_MSI
1042 default PCI_MSI
1043 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1044 ---help---
1045 A local APIC (Advanced Programmable Interrupt Controller) is an
1046 integrated interrupt controller in the CPU. If you have a single-CPU
1047 system which has a processor with a local APIC, you can say Y here to
1048 enable and use it. If you say Y here even though your machine doesn't
1049 have a local APIC, then the kernel will still run with no slowdown at
1050 all. The local APIC supports CPU-generated self-interrupts (timer,
1051 performance counters), and the NMI watchdog which detects hard
1052 lockups.
1053
1054config X86_UP_IOAPIC
1055 bool "IO-APIC support on uniprocessors"
1056 depends on X86_UP_APIC
1057 ---help---
1058 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1059 SMP-capable replacement for PC-style interrupt controllers. Most
1060 SMP systems and many recent uniprocessor systems have one.
1061
1062 If you have a single-CPU system with an IO-APIC, you can say Y here
1063 to use it. If you say Y here even though your machine doesn't have
1064 an IO-APIC, then the kernel will still run with no slowdown at all.
1065
1066config X86_LOCAL_APIC
1067 def_bool y
1068 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1069 select IRQ_DOMAIN_HIERARCHY
1070 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1071
1072config X86_IO_APIC
1073 def_bool y
1074 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1075
1076config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1077 bool "Reroute for broken boot IRQs"
1078 depends on X86_IO_APIC
1079 ---help---
1080 This option enables a workaround that fixes a source of
1081 spurious interrupts. This is recommended when threaded
1082 interrupt handling is used on systems where the generation of
1083 superfluous "boot interrupts" cannot be disabled.
1084
1085 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1086 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1087 kernel does during interrupt handling). On chipsets where this
1088 boot IRQ generation cannot be disabled, this workaround keeps
1089 the original IRQ line masked so that only the equivalent "boot
1090 IRQ" is delivered to the CPUs. The workaround also tells the
1091 kernel to set up the IRQ handler on the boot IRQ line. In this
1092 way only one interrupt is delivered to the kernel. Otherwise
1093 the spurious second interrupt may cause the kernel to bring
1094 down (vital) interrupt lines.
1095
1096 Only affects "broken" chipsets. Interrupt sharing may be
1097 increased on these systems.
1098
1099config X86_MCE
1100 bool "Machine Check / overheating reporting"
1101 select GENERIC_ALLOCATOR
1102 default y
1103 ---help---
1104 Machine Check support allows the processor to notify the
1105 kernel if it detects a problem (e.g. overheating, data corruption).
1106 The action the kernel takes depends on the severity of the problem,
1107 ranging from warning messages to halting the machine.
1108
1109config X86_MCELOG_LEGACY
1110 bool "Support for deprecated /dev/mcelog character device"
1111 depends on X86_MCE
1112 ---help---
1113 Enable support for /dev/mcelog which is needed by the old mcelog
1114 userspace logging daemon. Consider switching to the new generation
1115 rasdaemon solution.
1116
1117config X86_MCE_INTEL
1118 def_bool y
1119 prompt "Intel MCE features"
1120 depends on X86_MCE && X86_LOCAL_APIC
1121 ---help---
1122 Additional support for intel specific MCE features such as
1123 the thermal monitor.
1124
1125config X86_MCE_AMD
1126 def_bool y
1127 prompt "AMD MCE features"
1128 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1129 ---help---
1130 Additional support for AMD specific MCE features such as
1131 the DRAM Error Threshold.
1132
1133config X86_ANCIENT_MCE
1134 bool "Support for old Pentium 5 / WinChip machine checks"
1135 depends on X86_32 && X86_MCE
1136 ---help---
1137 Include support for machine check handling on old Pentium 5 or WinChip
1138 systems. These typically need to be enabled explicitly on the command
1139 line.
1140
1141config X86_MCE_THRESHOLD
1142 depends on X86_MCE_AMD || X86_MCE_INTEL
1143 def_bool y
1144
1145config X86_MCE_INJECT
1146 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1147 tristate "Machine check injector support"
1148 ---help---
1149 Provide support for injecting machine checks for testing purposes.
1150 If you don't know what a machine check is and you don't do kernel
1151 QA it is safe to say n.
1152
1153config X86_THERMAL_VECTOR
1154 def_bool y
1155 depends on X86_MCE_INTEL
1156
1157source "arch/x86/events/Kconfig"
1158
1159config X86_LEGACY_VM86
1160 bool "Legacy VM86 support"
1161 default n
1162 depends on X86_32
1163 ---help---
1164 This option allows user programs to put the CPU into V8086
1165 mode, which is an 80286-era approximation of 16-bit real mode.
1166
1167 Some very old versions of X and/or vbetool require this option
1168 for user mode setting. Similarly, DOSEMU will use it if
1169 available to accelerate real mode DOS programs. However, any
1170 recent version of DOSEMU, X, or vbetool should be fully
1171 functional even without kernel VM86 support, as they will all
1172 fall back to software emulation. Nevertheless, if you are using
1173 a 16-bit DOS program where 16-bit performance matters, vm86
1174 mode might be faster than emulation and you might want to
1175 enable this option.
1176
1177 Note that any app that works on a 64-bit kernel is unlikely to
1178 need this option, as 64-bit kernels don't, and can't, support
1179 V8086 mode. This option is also unrelated to 16-bit protected
1180 mode and is not needed to run most 16-bit programs under Wine.
1181
1182 Enabling this option increases the complexity of the kernel
1183 and slows down exception handling a tiny bit.
1184
1185 If unsure, say N here.
1186
1187config VM86
1188 bool
1189 default X86_LEGACY_VM86
1190
1191config X86_16BIT
1192 bool "Enable support for 16-bit segments" if EXPERT
1193 default y
1194 depends on MODIFY_LDT_SYSCALL
1195 ---help---
1196 This option is required by programs like Wine to run 16-bit
1197 protected mode legacy code on x86 processors. Disabling
1198 this option saves about 300 bytes on i386, or around 6K text
1199 plus 16K runtime memory on x86-64,
1200
1201config X86_ESPFIX32
1202 def_bool y
1203 depends on X86_16BIT && X86_32
1204
1205config X86_ESPFIX64
1206 def_bool y
1207 depends on X86_16BIT && X86_64
1208
1209config X86_VSYSCALL_EMULATION
1210 bool "Enable vsyscall emulation" if EXPERT
1211 default y
1212 depends on X86_64
1213 ---help---
1214 This enables emulation of the legacy vsyscall page. Disabling
1215 it is roughly equivalent to booting with vsyscall=none, except
1216 that it will also disable the helpful warning if a program
1217 tries to use a vsyscall. With this option set to N, offending
1218 programs will just segfault, citing addresses of the form
1219 0xffffffffff600?00.
1220
1221 This option is required by many programs built before 2013, and
1222 care should be used even with newer programs if set to N.
1223
1224 Disabling this option saves about 7K of kernel size and
1225 possibly 4K of additional runtime pagetable memory.
1226
1227config TOSHIBA
1228 tristate "Toshiba Laptop support"
1229 depends on X86_32
1230 ---help---
1231 This adds a driver to safely access the System Management Mode of
1232 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1233 not work on models with a Phoenix BIOS. The System Management Mode
1234 is used to set the BIOS and power saving options on Toshiba portables.
1235
1236 For information on utilities to make use of this driver see the
1237 Toshiba Linux utilities web site at:
1238 <http://www.buzzard.org.uk/toshiba/>.
1239
1240 Say Y if you intend to run this kernel on a Toshiba portable.
1241 Say N otherwise.
1242
1243config I8K
1244 tristate "Dell i8k legacy laptop support"
1245 select HWMON
1246 select SENSORS_DELL_SMM
1247 ---help---
1248 This option enables legacy /proc/i8k userspace interface in hwmon
1249 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1250 temperature and allows controlling fan speeds of Dell laptops via
1251 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1252 it reports also power and hotkey status. For fan speed control is
1253 needed userspace package i8kutils.
1254
1255 Say Y if you intend to run this kernel on old Dell laptops or want to
1256 use userspace package i8kutils.
1257 Say N otherwise.
1258
1259config X86_REBOOTFIXUPS
1260 bool "Enable X86 board specific fixups for reboot"
1261 depends on X86_32
1262 ---help---
1263 This enables chipset and/or board specific fixups to be done
1264 in order to get reboot to work correctly. This is only needed on
1265 some combinations of hardware and BIOS. The symptom, for which
1266 this config is intended, is when reboot ends with a stalled/hung
1267 system.
1268
1269 Currently, the only fixup is for the Geode machines using
1270 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1271
1272 Say Y if you want to enable the fixup. Currently, it's safe to
1273 enable this option even if you don't need it.
1274 Say N otherwise.
1275
1276config MICROCODE
1277 bool "CPU microcode loading support"
1278 default y
1279 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1280 select FW_LOADER
1281 ---help---
1282 If you say Y here, you will be able to update the microcode on
1283 Intel and AMD processors. The Intel support is for the IA32 family,
1284 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1285 AMD support is for families 0x10 and later. You will obviously need
1286 the actual microcode binary data itself which is not shipped with
1287 the Linux kernel.
1288
1289 The preferred method to load microcode from a detached initrd is described
1290 in Documentation/x86/microcode.txt. For that you need to enable
1291 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1292 initrd for microcode blobs.
1293
1294 In addition, you can build the microcode into the kernel. For that you
1295 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1296 config option.
1297
1298config MICROCODE_INTEL
1299 bool "Intel microcode loading support"
1300 depends on MICROCODE
1301 default MICROCODE
1302 select FW_LOADER
1303 ---help---
1304 This options enables microcode patch loading support for Intel
1305 processors.
1306
1307 For the current Intel microcode data package go to
1308 <https://downloadcenter.intel.com> and search for
1309 'Linux Processor Microcode Data File'.
1310
1311config MICROCODE_AMD
1312 bool "AMD microcode loading support"
1313 depends on MICROCODE
1314 select FW_LOADER
1315 ---help---
1316 If you select this option, microcode patch loading support for AMD
1317 processors will be enabled.
1318
1319config MICROCODE_OLD_INTERFACE
1320 def_bool y
1321 depends on MICROCODE
1322
1323config X86_MSR
1324 tristate "/dev/cpu/*/msr - Model-specific register support"
1325 ---help---
1326 This device gives privileged processes access to the x86
1327 Model-Specific Registers (MSRs). It is a character device with
1328 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1329 MSR accesses are directed to a specific CPU on multi-processor
1330 systems.
1331
1332config X86_CPUID
1333 tristate "/dev/cpu/*/cpuid - CPU information support"
1334 ---help---
1335 This device gives processes access to the x86 CPUID instruction to
1336 be executed on a specific processor. It is a character device
1337 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1338 /dev/cpu/31/cpuid.
1339
1340choice
1341 prompt "High Memory Support"
1342 default HIGHMEM4G
1343 depends on X86_32
1344
1345config NOHIGHMEM
1346 bool "off"
1347 ---help---
1348 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1349 However, the address space of 32-bit x86 processors is only 4
1350 Gigabytes large. That means that, if you have a large amount of
1351 physical memory, not all of it can be "permanently mapped" by the
1352 kernel. The physical memory that's not permanently mapped is called
1353 "high memory".
1354
1355 If you are compiling a kernel which will never run on a machine with
1356 more than 1 Gigabyte total physical RAM, answer "off" here (default
1357 choice and suitable for most users). This will result in a "3GB/1GB"
1358 split: 3GB are mapped so that each process sees a 3GB virtual memory
1359 space and the remaining part of the 4GB virtual memory space is used
1360 by the kernel to permanently map as much physical memory as
1361 possible.
1362
1363 If the machine has between 1 and 4 Gigabytes physical RAM, then
1364 answer "4GB" here.
1365
1366 If more than 4 Gigabytes is used then answer "64GB" here. This
1367 selection turns Intel PAE (Physical Address Extension) mode on.
1368 PAE implements 3-level paging on IA32 processors. PAE is fully
1369 supported by Linux, PAE mode is implemented on all recent Intel
1370 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1371 then the kernel will not boot on CPUs that don't support PAE!
1372
1373 The actual amount of total physical memory will either be
1374 auto detected or can be forced by using a kernel command line option
1375 such as "mem=256M". (Try "man bootparam" or see the documentation of
1376 your boot loader (lilo or loadlin) about how to pass options to the
1377 kernel at boot time.)
1378
1379 If unsure, say "off".
1380
1381config HIGHMEM4G
1382 bool "4GB"
1383 ---help---
1384 Select this if you have a 32-bit processor and between 1 and 4
1385 gigabytes of physical RAM.
1386
1387config HIGHMEM64G
1388 bool "64GB"
1389 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1390 select X86_PAE
1391 ---help---
1392 Select this if you have a 32-bit processor and more than 4
1393 gigabytes of physical RAM.
1394
1395endchoice
1396
1397choice
1398 prompt "Memory split" if EXPERT
1399 default VMSPLIT_3G
1400 depends on X86_32
1401 ---help---
1402 Select the desired split between kernel and user memory.
1403
1404 If the address range available to the kernel is less than the
1405 physical memory installed, the remaining memory will be available
1406 as "high memory". Accessing high memory is a little more costly
1407 than low memory, as it needs to be mapped into the kernel first.
1408 Note that increasing the kernel address space limits the range
1409 available to user programs, making the address space there
1410 tighter. Selecting anything other than the default 3G/1G split
1411 will also likely make your kernel incompatible with binary-only
1412 kernel modules.
1413
1414 If you are not absolutely sure what you are doing, leave this
1415 option alone!
1416
1417 config VMSPLIT_3G
1418 bool "3G/1G user/kernel split"
1419 config VMSPLIT_3G_OPT
1420 depends on !X86_PAE
1421 bool "3G/1G user/kernel split (for full 1G low memory)"
1422 config VMSPLIT_2G
1423 bool "2G/2G user/kernel split"
1424 config VMSPLIT_2G_OPT
1425 depends on !X86_PAE
1426 bool "2G/2G user/kernel split (for full 2G low memory)"
1427 config VMSPLIT_1G
1428 bool "1G/3G user/kernel split"
1429endchoice
1430
1431config PAGE_OFFSET
1432 hex
1433 default 0xB0000000 if VMSPLIT_3G_OPT
1434 default 0x80000000 if VMSPLIT_2G
1435 default 0x78000000 if VMSPLIT_2G_OPT
1436 default 0x40000000 if VMSPLIT_1G
1437 default 0xC0000000
1438 depends on X86_32
1439
1440config HIGHMEM
1441 def_bool y
1442 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1443
1444config X86_PAE
1445 bool "PAE (Physical Address Extension) Support"
1446 depends on X86_32 && !HIGHMEM4G
1447 select PHYS_ADDR_T_64BIT
1448 select SWIOTLB
1449 ---help---
1450 PAE is required for NX support, and furthermore enables
1451 larger swapspace support for non-overcommit purposes. It
1452 has the cost of more pagetable lookup overhead, and also
1453 consumes more pagetable space per process.
1454
1455config X86_5LEVEL
1456 bool "Enable 5-level page tables support"
1457 select DYNAMIC_MEMORY_LAYOUT
1458 select SPARSEMEM_VMEMMAP
1459 depends on X86_64
1460 ---help---
1461 5-level paging enables access to larger address space:
1462 upto 128 PiB of virtual address space and 4 PiB of
1463 physical address space.
1464
1465 It will be supported by future Intel CPUs.
1466
1467 A kernel with the option enabled can be booted on machines that
1468 support 4- or 5-level paging.
1469
1470 See Documentation/x86/x86_64/5level-paging.txt for more
1471 information.
1472
1473 Say N if unsure.
1474
1475config X86_DIRECT_GBPAGES
1476 def_bool y
1477 depends on X86_64 && !DEBUG_PAGEALLOC
1478 ---help---
1479 Certain kernel features effectively disable kernel
1480 linear 1 GB mappings (even if the CPU otherwise
1481 supports them), so don't confuse the user by printing
1482 that we have them enabled.
1483
1484config ARCH_HAS_MEM_ENCRYPT
1485 def_bool y
1486
1487config AMD_MEM_ENCRYPT
1488 bool "AMD Secure Memory Encryption (SME) support"
1489 depends on X86_64 && CPU_SUP_AMD
1490 select DYNAMIC_PHYSICAL_MASK
1491 ---help---
1492 Say yes to enable support for the encryption of system memory.
1493 This requires an AMD processor that supports Secure Memory
1494 Encryption (SME).
1495
1496config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1497 bool "Activate AMD Secure Memory Encryption (SME) by default"
1498 default y
1499 depends on AMD_MEM_ENCRYPT
1500 ---help---
1501 Say yes to have system memory encrypted by default if running on
1502 an AMD processor that supports Secure Memory Encryption (SME).
1503
1504 If set to Y, then the encryption of system memory can be
1505 deactivated with the mem_encrypt=off command line option.
1506
1507 If set to N, then the encryption of system memory can be
1508 activated with the mem_encrypt=on command line option.
1509
1510config ARCH_USE_MEMREMAP_PROT
1511 def_bool y
1512 depends on AMD_MEM_ENCRYPT
1513
1514# Common NUMA Features
1515config NUMA
1516 bool "Numa Memory Allocation and Scheduler Support"
1517 depends on SMP
1518 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1519 default y if X86_BIGSMP
1520 ---help---
1521 Enable NUMA (Non Uniform Memory Access) support.
1522
1523 The kernel will try to allocate memory used by a CPU on the
1524 local memory controller of the CPU and add some more
1525 NUMA awareness to the kernel.
1526
1527 For 64-bit this is recommended if the system is Intel Core i7
1528 (or later), AMD Opteron, or EM64T NUMA.
1529
1530 For 32-bit this is only needed if you boot a 32-bit
1531 kernel on a 64-bit NUMA platform.
1532
1533 Otherwise, you should say N.
1534
1535config AMD_NUMA
1536 def_bool y
1537 prompt "Old style AMD Opteron NUMA detection"
1538 depends on X86_64 && NUMA && PCI
1539 ---help---
1540 Enable AMD NUMA node topology detection. You should say Y here if
1541 you have a multi processor AMD system. This uses an old method to
1542 read the NUMA configuration directly from the builtin Northbridge
1543 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1544 which also takes priority if both are compiled in.
1545
1546config X86_64_ACPI_NUMA
1547 def_bool y
1548 prompt "ACPI NUMA detection"
1549 depends on X86_64 && NUMA && ACPI && PCI
1550 select ACPI_NUMA
1551 ---help---
1552 Enable ACPI SRAT based node topology detection.
1553
1554# Some NUMA nodes have memory ranges that span
1555# other nodes. Even though a pfn is valid and
1556# between a node's start and end pfns, it may not
1557# reside on that node. See memmap_init_zone()
1558# for details.
1559config NODES_SPAN_OTHER_NODES
1560 def_bool y
1561 depends on X86_64_ACPI_NUMA
1562
1563config NUMA_EMU
1564 bool "NUMA emulation"
1565 depends on NUMA
1566 ---help---
1567 Enable NUMA emulation. A flat machine will be split
1568 into virtual nodes when booted with "numa=fake=N", where N is the
1569 number of nodes. This is only useful for debugging.
1570
1571config NODES_SHIFT
1572 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1573 range 1 10
1574 default "10" if MAXSMP
1575 default "6" if X86_64
1576 default "3"
1577 depends on NEED_MULTIPLE_NODES
1578 ---help---
1579 Specify the maximum number of NUMA Nodes available on the target
1580 system. Increases memory reserved to accommodate various tables.
1581
1582config ARCH_HAVE_MEMORY_PRESENT
1583 def_bool y
1584 depends on X86_32 && DISCONTIGMEM
1585
1586config ARCH_FLATMEM_ENABLE
1587 def_bool y
1588 depends on X86_32 && !NUMA
1589
1590config ARCH_DISCONTIGMEM_ENABLE
1591 def_bool y
1592 depends on NUMA && X86_32
1593
1594config ARCH_DISCONTIGMEM_DEFAULT
1595 def_bool y
1596 depends on NUMA && X86_32
1597
1598config ARCH_SPARSEMEM_ENABLE
1599 def_bool y
1600 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1601 select SPARSEMEM_STATIC if X86_32
1602 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1603
1604config ARCH_SPARSEMEM_DEFAULT
1605 def_bool y
1606 depends on X86_64
1607
1608config ARCH_SELECT_MEMORY_MODEL
1609 def_bool y
1610 depends on ARCH_SPARSEMEM_ENABLE
1611
1612config ARCH_MEMORY_PROBE
1613 bool "Enable sysfs memory/probe interface"
1614 depends on X86_64 && MEMORY_HOTPLUG
1615 help
1616 This option enables a sysfs memory/probe interface for testing.
1617 See Documentation/memory-hotplug.txt for more information.
1618 If you are unsure how to answer this question, answer N.
1619
1620config ARCH_PROC_KCORE_TEXT
1621 def_bool y
1622 depends on X86_64 && PROC_KCORE
1623
1624config ILLEGAL_POINTER_VALUE
1625 hex
1626 default 0 if X86_32
1627 default 0xdead000000000000 if X86_64
1628
1629config X86_PMEM_LEGACY_DEVICE
1630 bool
1631
1632config X86_PMEM_LEGACY
1633 tristate "Support non-standard NVDIMMs and ADR protected memory"
1634 depends on PHYS_ADDR_T_64BIT
1635 depends on BLK_DEV
1636 select X86_PMEM_LEGACY_DEVICE
1637 select LIBNVDIMM
1638 help
1639 Treat memory marked using the non-standard e820 type of 12 as used
1640 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1641 The kernel will offer these regions to the 'pmem' driver so
1642 they can be used for persistent storage.
1643
1644 Say Y if unsure.
1645
1646config HIGHPTE
1647 bool "Allocate 3rd-level pagetables from highmem"
1648 depends on HIGHMEM
1649 ---help---
1650 The VM uses one page table entry for each page of physical memory.
1651 For systems with a lot of RAM, this can be wasteful of precious
1652 low memory. Setting this option will put user-space page table
1653 entries in high memory.
1654
1655config X86_CHECK_BIOS_CORRUPTION
1656 bool "Check for low memory corruption"
1657 ---help---
1658 Periodically check for memory corruption in low memory, which
1659 is suspected to be caused by BIOS. Even when enabled in the
1660 configuration, it is disabled at runtime. Enable it by
1661 setting "memory_corruption_check=1" on the kernel command
1662 line. By default it scans the low 64k of memory every 60
1663 seconds; see the memory_corruption_check_size and
1664 memory_corruption_check_period parameters in
1665 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1666
1667 When enabled with the default parameters, this option has
1668 almost no overhead, as it reserves a relatively small amount
1669 of memory and scans it infrequently. It both detects corruption
1670 and prevents it from affecting the running system.
1671
1672 It is, however, intended as a diagnostic tool; if repeatable
1673 BIOS-originated corruption always affects the same memory,
1674 you can use memmap= to prevent the kernel from using that
1675 memory.
1676
1677config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1678 bool "Set the default setting of memory_corruption_check"
1679 depends on X86_CHECK_BIOS_CORRUPTION
1680 default y
1681 ---help---
1682 Set whether the default state of memory_corruption_check is
1683 on or off.
1684
1685config X86_RESERVE_LOW
1686 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1687 default 64
1688 range 4 640
1689 ---help---
1690 Specify the amount of low memory to reserve for the BIOS.
1691
1692 The first page contains BIOS data structures that the kernel
1693 must not use, so that page must always be reserved.
1694
1695 By default we reserve the first 64K of physical RAM, as a
1696 number of BIOSes are known to corrupt that memory range
1697 during events such as suspend/resume or monitor cable
1698 insertion, so it must not be used by the kernel.
1699
1700 You can set this to 4 if you are absolutely sure that you
1701 trust the BIOS to get all its memory reservations and usages
1702 right. If you know your BIOS have problems beyond the
1703 default 64K area, you can set this to 640 to avoid using the
1704 entire low memory range.
1705
1706 If you have doubts about the BIOS (e.g. suspend/resume does
1707 not work or there's kernel crashes after certain hardware
1708 hotplug events) then you might want to enable
1709 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1710 typical corruption patterns.
1711
1712 Leave this to the default value of 64 if you are unsure.
1713
1714config MATH_EMULATION
1715 bool
1716 depends on MODIFY_LDT_SYSCALL
1717 prompt "Math emulation" if X86_32
1718 ---help---
1719 Linux can emulate a math coprocessor (used for floating point
1720 operations) if you don't have one. 486DX and Pentium processors have
1721 a math coprocessor built in, 486SX and 386 do not, unless you added
1722 a 487DX or 387, respectively. (The messages during boot time can
1723 give you some hints here ["man dmesg"].) Everyone needs either a
1724 coprocessor or this emulation.
1725
1726 If you don't have a math coprocessor, you need to say Y here; if you
1727 say Y here even though you have a coprocessor, the coprocessor will
1728 be used nevertheless. (This behavior can be changed with the kernel
1729 command line option "no387", which comes handy if your coprocessor
1730 is broken. Try "man bootparam" or see the documentation of your boot
1731 loader (lilo or loadlin) about how to pass options to the kernel at
1732 boot time.) This means that it is a good idea to say Y here if you
1733 intend to use this kernel on different machines.
1734
1735 More information about the internals of the Linux math coprocessor
1736 emulation can be found in <file:arch/x86/math-emu/README>.
1737
1738 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1739 kernel, it won't hurt.
1740
1741config MTRR
1742 def_bool y
1743 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1744 ---help---
1745 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1746 the Memory Type Range Registers (MTRRs) may be used to control
1747 processor access to memory ranges. This is most useful if you have
1748 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1749 allows bus write transfers to be combined into a larger transfer
1750 before bursting over the PCI/AGP bus. This can increase performance
1751 of image write operations 2.5 times or more. Saying Y here creates a
1752 /proc/mtrr file which may be used to manipulate your processor's
1753 MTRRs. Typically the X server should use this.
1754
1755 This code has a reasonably generic interface so that similar
1756 control registers on other processors can be easily supported
1757 as well:
1758
1759 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1760 Registers (ARRs) which provide a similar functionality to MTRRs. For
1761 these, the ARRs are used to emulate the MTRRs.
1762 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1763 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1764 write-combining. All of these processors are supported by this code
1765 and it makes sense to say Y here if you have one of them.
1766
1767 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1768 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1769 can lead to all sorts of problems, so it's good to say Y here.
1770
1771 You can safely say Y even if your machine doesn't have MTRRs, you'll
1772 just add about 9 KB to your kernel.
1773
1774 See <file:Documentation/x86/mtrr.txt> for more information.
1775
1776config MTRR_SANITIZER
1777 def_bool y
1778 prompt "MTRR cleanup support"
1779 depends on MTRR
1780 ---help---
1781 Convert MTRR layout from continuous to discrete, so X drivers can
1782 add writeback entries.
1783
1784 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1785 The largest mtrr entry size for a continuous block can be set with
1786 mtrr_chunk_size.
1787
1788 If unsure, say Y.
1789
1790config MTRR_SANITIZER_ENABLE_DEFAULT
1791 int "MTRR cleanup enable value (0-1)"
1792 range 0 1
1793 default "0"
1794 depends on MTRR_SANITIZER
1795 ---help---
1796 Enable mtrr cleanup default value
1797
1798config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1799 int "MTRR cleanup spare reg num (0-7)"
1800 range 0 7
1801 default "1"
1802 depends on MTRR_SANITIZER
1803 ---help---
1804 mtrr cleanup spare entries default, it can be changed via
1805 mtrr_spare_reg_nr=N on the kernel command line.
1806
1807config X86_PAT
1808 def_bool y
1809 prompt "x86 PAT support" if EXPERT
1810 depends on MTRR
1811 ---help---
1812 Use PAT attributes to setup page level cache control.
1813
1814 PATs are the modern equivalents of MTRRs and are much more
1815 flexible than MTRRs.
1816
1817 Say N here if you see bootup problems (boot crash, boot hang,
1818 spontaneous reboots) or a non-working video driver.
1819
1820 If unsure, say Y.
1821
1822config ARCH_USES_PG_UNCACHED
1823 def_bool y
1824 depends on X86_PAT
1825
1826config ARCH_RANDOM
1827 def_bool y
1828 prompt "x86 architectural random number generator" if EXPERT
1829 ---help---
1830 Enable the x86 architectural RDRAND instruction
1831 (Intel Bull Mountain technology) to generate random numbers.
1832 If supported, this is a high bandwidth, cryptographically
1833 secure hardware random number generator.
1834
1835config X86_SMAP
1836 def_bool y
1837 prompt "Supervisor Mode Access Prevention" if EXPERT
1838 ---help---
1839 Supervisor Mode Access Prevention (SMAP) is a security
1840 feature in newer Intel processors. There is a small
1841 performance cost if this enabled and turned on; there is
1842 also a small increase in the kernel size if this is enabled.
1843
1844 If unsure, say Y.
1845
1846config X86_INTEL_UMIP
1847 def_bool y
1848 depends on CPU_SUP_INTEL
1849 prompt "Intel User Mode Instruction Prevention" if EXPERT
1850 ---help---
1851 The User Mode Instruction Prevention (UMIP) is a security
1852 feature in newer Intel processors. If enabled, a general
1853 protection fault is issued if the SGDT, SLDT, SIDT, SMSW
1854 or STR instructions are executed in user mode. These instructions
1855 unnecessarily expose information about the hardware state.
1856
1857 The vast majority of applications do not use these instructions.
1858 For the very few that do, software emulation is provided in
1859 specific cases in protected and virtual-8086 modes. Emulated
1860 results are dummy.
1861
1862config X86_INTEL_MPX
1863 prompt "Intel MPX (Memory Protection Extensions)"
1864 def_bool n
1865 # Note: only available in 64-bit mode due to VMA flags shortage
1866 depends on CPU_SUP_INTEL && X86_64
1867 select ARCH_USES_HIGH_VMA_FLAGS
1868 ---help---
1869 MPX provides hardware features that can be used in
1870 conjunction with compiler-instrumented code to check
1871 memory references. It is designed to detect buffer
1872 overflow or underflow bugs.
1873
1874 This option enables running applications which are
1875 instrumented or otherwise use MPX. It does not use MPX
1876 itself inside the kernel or to protect the kernel
1877 against bad memory references.
1878
1879 Enabling this option will make the kernel larger:
1880 ~8k of kernel text and 36 bytes of data on a 64-bit
1881 defconfig. It adds a long to the 'mm_struct' which
1882 will increase the kernel memory overhead of each
1883 process and adds some branches to paths used during
1884 exec() and munmap().
1885
1886 For details, see Documentation/x86/intel_mpx.txt
1887
1888 If unsure, say N.
1889
1890config X86_INTEL_MEMORY_PROTECTION_KEYS
1891 prompt "Intel Memory Protection Keys"
1892 def_bool y
1893 # Note: only available in 64-bit mode
1894 depends on CPU_SUP_INTEL && X86_64
1895 select ARCH_USES_HIGH_VMA_FLAGS
1896 select ARCH_HAS_PKEYS
1897 ---help---
1898 Memory Protection Keys provides a mechanism for enforcing
1899 page-based protections, but without requiring modification of the
1900 page tables when an application changes protection domains.
1901
1902 For details, see Documentation/x86/protection-keys.txt
1903
1904 If unsure, say y.
1905
1906config EFI
1907 bool "EFI runtime service support"
1908 depends on ACPI
1909 select UCS2_STRING
1910 select EFI_RUNTIME_WRAPPERS
1911 ---help---
1912 This enables the kernel to use EFI runtime services that are
1913 available (such as the EFI variable services).
1914
1915 This option is only useful on systems that have EFI firmware.
1916 In addition, you should use the latest ELILO loader available
1917 at <http://elilo.sourceforge.net> in order to take advantage
1918 of EFI runtime services. However, even with this option, the
1919 resultant kernel should continue to boot on existing non-EFI
1920 platforms.
1921
1922config EFI_STUB
1923 bool "EFI stub support"
1924 depends on EFI && !X86_USE_3DNOW
1925 select RELOCATABLE
1926 ---help---
1927 This kernel feature allows a bzImage to be loaded directly
1928 by EFI firmware without the use of a bootloader.
1929
1930 See Documentation/efi-stub.txt for more information.
1931
1932config EFI_MIXED
1933 bool "EFI mixed-mode support"
1934 depends on EFI_STUB && X86_64
1935 ---help---
1936 Enabling this feature allows a 64-bit kernel to be booted
1937 on a 32-bit firmware, provided that your CPU supports 64-bit
1938 mode.
1939
1940 Note that it is not possible to boot a mixed-mode enabled
1941 kernel via the EFI boot stub - a bootloader that supports
1942 the EFI handover protocol must be used.
1943
1944 If unsure, say N.
1945
1946config SECCOMP
1947 def_bool y
1948 prompt "Enable seccomp to safely compute untrusted bytecode"
1949 ---help---
1950 This kernel feature is useful for number crunching applications
1951 that may need to compute untrusted bytecode during their
1952 execution. By using pipes or other transports made available to
1953 the process as file descriptors supporting the read/write
1954 syscalls, it's possible to isolate those applications in
1955 their own address space using seccomp. Once seccomp is
1956 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1957 and the task is only allowed to execute a few safe syscalls
1958 defined by each seccomp mode.
1959
1960 If unsure, say Y. Only embedded should say N here.
1961
1962source kernel/Kconfig.hz
1963
1964config KEXEC
1965 bool "kexec system call"
1966 select KEXEC_CORE
1967 ---help---
1968 kexec is a system call that implements the ability to shutdown your
1969 current kernel, and to start another kernel. It is like a reboot
1970 but it is independent of the system firmware. And like a reboot
1971 you can start any kernel with it, not just Linux.
1972
1973 The name comes from the similarity to the exec system call.
1974
1975 It is an ongoing process to be certain the hardware in a machine
1976 is properly shutdown, so do not be surprised if this code does not
1977 initially work for you. As of this writing the exact hardware
1978 interface is strongly in flux, so no good recommendation can be
1979 made.
1980
1981config KEXEC_FILE
1982 bool "kexec file based system call"
1983 select KEXEC_CORE
1984 select BUILD_BIN2C
1985 depends on X86_64
1986 depends on CRYPTO=y
1987 depends on CRYPTO_SHA256=y
1988 ---help---
1989 This is new version of kexec system call. This system call is
1990 file based and takes file descriptors as system call argument
1991 for kernel and initramfs as opposed to list of segments as
1992 accepted by previous system call.
1993
1994config ARCH_HAS_KEXEC_PURGATORY
1995 def_bool KEXEC_FILE
1996
1997config KEXEC_VERIFY_SIG
1998 bool "Verify kernel signature during kexec_file_load() syscall"
1999 depends on KEXEC_FILE
2000 ---help---
2001 This option makes kernel signature verification mandatory for
2002 the kexec_file_load() syscall.
2003
2004 In addition to that option, you need to enable signature
2005 verification for the corresponding kernel image type being
2006 loaded in order for this to work.
2007
2008config KEXEC_BZIMAGE_VERIFY_SIG
2009 bool "Enable bzImage signature verification support"
2010 depends on KEXEC_VERIFY_SIG
2011 depends on SIGNED_PE_FILE_VERIFICATION
2012 select SYSTEM_TRUSTED_KEYRING
2013 ---help---
2014 Enable bzImage signature verification support.
2015
2016config CRASH_DUMP
2017 bool "kernel crash dumps"
2018 depends on X86_64 || (X86_32 && HIGHMEM)
2019 ---help---
2020 Generate crash dump after being started by kexec.
2021 This should be normally only set in special crash dump kernels
2022 which are loaded in the main kernel with kexec-tools into
2023 a specially reserved region and then later executed after
2024 a crash by kdump/kexec. The crash dump kernel must be compiled
2025 to a memory address not used by the main kernel or BIOS using
2026 PHYSICAL_START, or it must be built as a relocatable image
2027 (CONFIG_RELOCATABLE=y).
2028 For more details see Documentation/kdump/kdump.txt
2029
2030config KEXEC_JUMP
2031 bool "kexec jump"
2032 depends on KEXEC && HIBERNATION
2033 ---help---
2034 Jump between original kernel and kexeced kernel and invoke
2035 code in physical address mode via KEXEC
2036
2037config PHYSICAL_START
2038 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2039 default "0x1000000"
2040 ---help---
2041 This gives the physical address where the kernel is loaded.
2042
2043 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2044 bzImage will decompress itself to above physical address and
2045 run from there. Otherwise, bzImage will run from the address where
2046 it has been loaded by the boot loader and will ignore above physical
2047 address.
2048
2049 In normal kdump cases one does not have to set/change this option
2050 as now bzImage can be compiled as a completely relocatable image
2051 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2052 address. This option is mainly useful for the folks who don't want
2053 to use a bzImage for capturing the crash dump and want to use a
2054 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2055 to be specifically compiled to run from a specific memory area
2056 (normally a reserved region) and this option comes handy.
2057
2058 So if you are using bzImage for capturing the crash dump,
2059 leave the value here unchanged to 0x1000000 and set
2060 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2061 for capturing the crash dump change this value to start of
2062 the reserved region. In other words, it can be set based on
2063 the "X" value as specified in the "crashkernel=YM@XM"
2064 command line boot parameter passed to the panic-ed
2065 kernel. Please take a look at Documentation/kdump/kdump.txt
2066 for more details about crash dumps.
2067
2068 Usage of bzImage for capturing the crash dump is recommended as
2069 one does not have to build two kernels. Same kernel can be used
2070 as production kernel and capture kernel. Above option should have
2071 gone away after relocatable bzImage support is introduced. But it
2072 is present because there are users out there who continue to use
2073 vmlinux for dump capture. This option should go away down the
2074 line.
2075
2076 Don't change this unless you know what you are doing.
2077
2078config RELOCATABLE
2079 bool "Build a relocatable kernel"
2080 default y
2081 ---help---
2082 This builds a kernel image that retains relocation information
2083 so it can be loaded someplace besides the default 1MB.
2084 The relocations tend to make the kernel binary about 10% larger,
2085 but are discarded at runtime.
2086
2087 One use is for the kexec on panic case where the recovery kernel
2088 must live at a different physical address than the primary
2089 kernel.
2090
2091 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2092 it has been loaded at and the compile time physical address
2093 (CONFIG_PHYSICAL_START) is used as the minimum location.
2094
2095config RANDOMIZE_BASE
2096 bool "Randomize the address of the kernel image (KASLR)"
2097 depends on RELOCATABLE
2098 default y
2099 ---help---
2100 In support of Kernel Address Space Layout Randomization (KASLR),
2101 this randomizes the physical address at which the kernel image
2102 is decompressed and the virtual address where the kernel
2103 image is mapped, as a security feature that deters exploit
2104 attempts relying on knowledge of the location of kernel
2105 code internals.
2106
2107 On 64-bit, the kernel physical and virtual addresses are
2108 randomized separately. The physical address will be anywhere
2109 between 16MB and the top of physical memory (up to 64TB). The
2110 virtual address will be randomized from 16MB up to 1GB (9 bits
2111 of entropy). Note that this also reduces the memory space
2112 available to kernel modules from 1.5GB to 1GB.
2113
2114 On 32-bit, the kernel physical and virtual addresses are
2115 randomized together. They will be randomized from 16MB up to
2116 512MB (8 bits of entropy).
2117
2118 Entropy is generated using the RDRAND instruction if it is
2119 supported. If RDTSC is supported, its value is mixed into
2120 the entropy pool as well. If neither RDRAND nor RDTSC are
2121 supported, then entropy is read from the i8254 timer. The
2122 usable entropy is limited by the kernel being built using
2123 2GB addressing, and that PHYSICAL_ALIGN must be at a
2124 minimum of 2MB. As a result, only 10 bits of entropy are
2125 theoretically possible, but the implementations are further
2126 limited due to memory layouts.
2127
2128 If unsure, say Y.
2129
2130# Relocation on x86 needs some additional build support
2131config X86_NEED_RELOCS
2132 def_bool y
2133 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2134
2135config PHYSICAL_ALIGN
2136 hex "Alignment value to which kernel should be aligned"
2137 default "0x200000"
2138 range 0x2000 0x1000000 if X86_32
2139 range 0x200000 0x1000000 if X86_64
2140 ---help---
2141 This value puts the alignment restrictions on physical address
2142 where kernel is loaded and run from. Kernel is compiled for an
2143 address which meets above alignment restriction.
2144
2145 If bootloader loads the kernel at a non-aligned address and
2146 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2147 address aligned to above value and run from there.
2148
2149 If bootloader loads the kernel at a non-aligned address and
2150 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2151 load address and decompress itself to the address it has been
2152 compiled for and run from there. The address for which kernel is
2153 compiled already meets above alignment restrictions. Hence the
2154 end result is that kernel runs from a physical address meeting
2155 above alignment restrictions.
2156
2157 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2158 this value must be a multiple of 0x200000.
2159
2160 Don't change this unless you know what you are doing.
2161
2162config DYNAMIC_MEMORY_LAYOUT
2163 bool
2164 ---help---
2165 This option makes base addresses of vmalloc and vmemmap as well as
2166 __PAGE_OFFSET movable during boot.
2167
2168config RANDOMIZE_MEMORY
2169 bool "Randomize the kernel memory sections"
2170 depends on X86_64
2171 depends on RANDOMIZE_BASE
2172 select DYNAMIC_MEMORY_LAYOUT
2173 default RANDOMIZE_BASE
2174 ---help---
2175 Randomizes the base virtual address of kernel memory sections
2176 (physical memory mapping, vmalloc & vmemmap). This security feature
2177 makes exploits relying on predictable memory locations less reliable.
2178
2179 The order of allocations remains unchanged. Entropy is generated in
2180 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2181 configuration have in average 30,000 different possible virtual
2182 addresses for each memory section.
2183
2184 If unsure, say Y.
2185
2186config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2187 hex "Physical memory mapping padding" if EXPERT
2188 depends on RANDOMIZE_MEMORY
2189 default "0xa" if MEMORY_HOTPLUG
2190 default "0x0"
2191 range 0x1 0x40 if MEMORY_HOTPLUG
2192 range 0x0 0x40
2193 ---help---
2194 Define the padding in terabytes added to the existing physical
2195 memory size during kernel memory randomization. It is useful
2196 for memory hotplug support but reduces the entropy available for
2197 address randomization.
2198
2199 If unsure, leave at the default value.
2200
2201config HOTPLUG_CPU
2202 bool "Support for hot-pluggable CPUs"
2203 depends on SMP
2204 ---help---
2205 Say Y here to allow turning CPUs off and on. CPUs can be
2206 controlled through /sys/devices/system/cpu.
2207 ( Note: power management support will enable this option
2208 automatically on SMP systems. )
2209 Say N if you want to disable CPU hotplug.
2210
2211config BOOTPARAM_HOTPLUG_CPU0
2212 bool "Set default setting of cpu0_hotpluggable"
2213 default n
2214 depends on HOTPLUG_CPU
2215 ---help---
2216 Set whether default state of cpu0_hotpluggable is on or off.
2217
2218 Say Y here to enable CPU0 hotplug by default. If this switch
2219 is turned on, there is no need to give cpu0_hotplug kernel
2220 parameter and the CPU0 hotplug feature is enabled by default.
2221
2222 Please note: there are two known CPU0 dependencies if you want
2223 to enable the CPU0 hotplug feature either by this switch or by
2224 cpu0_hotplug kernel parameter.
2225
2226 First, resume from hibernate or suspend always starts from CPU0.
2227 So hibernate and suspend are prevented if CPU0 is offline.
2228
2229 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2230 offline if any interrupt can not migrate out of CPU0. There may
2231 be other CPU0 dependencies.
2232
2233 Please make sure the dependencies are under your control before
2234 you enable this feature.
2235
2236 Say N if you don't want to enable CPU0 hotplug feature by default.
2237 You still can enable the CPU0 hotplug feature at boot by kernel
2238 parameter cpu0_hotplug.
2239
2240config DEBUG_HOTPLUG_CPU0
2241 def_bool n
2242 prompt "Debug CPU0 hotplug"
2243 depends on HOTPLUG_CPU
2244 ---help---
2245 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2246 soon as possible and boots up userspace with CPU0 offlined. User
2247 can online CPU0 back after boot time.
2248
2249 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2250 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2251 compilation or giving cpu0_hotplug kernel parameter at boot.
2252
2253 If unsure, say N.
2254
2255config COMPAT_VDSO
2256 def_bool n
2257 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2258 depends on COMPAT_32
2259 ---help---
2260 Certain buggy versions of glibc will crash if they are
2261 presented with a 32-bit vDSO that is not mapped at the address
2262 indicated in its segment table.
2263
2264 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2265 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2266 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2267 the only released version with the bug, but OpenSUSE 9
2268 contains a buggy "glibc 2.3.2".
2269
2270 The symptom of the bug is that everything crashes on startup, saying:
2271 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2272
2273 Saying Y here changes the default value of the vdso32 boot
2274 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2275 This works around the glibc bug but hurts performance.
2276
2277 If unsure, say N: if you are compiling your own kernel, you
2278 are unlikely to be using a buggy version of glibc.
2279
2280choice
2281 prompt "vsyscall table for legacy applications"
2282 depends on X86_64
2283 default LEGACY_VSYSCALL_EMULATE
2284 help
2285 Legacy user code that does not know how to find the vDSO expects
2286 to be able to issue three syscalls by calling fixed addresses in
2287 kernel space. Since this location is not randomized with ASLR,
2288 it can be used to assist security vulnerability exploitation.
2289
2290 This setting can be changed at boot time via the kernel command
2291 line parameter vsyscall=[emulate|none].
2292
2293 On a system with recent enough glibc (2.14 or newer) and no
2294 static binaries, you can say None without a performance penalty
2295 to improve security.
2296
2297 If unsure, select "Emulate".
2298
2299 config LEGACY_VSYSCALL_EMULATE
2300 bool "Emulate"
2301 help
2302 The kernel traps and emulates calls into the fixed
2303 vsyscall address mapping. This makes the mapping
2304 non-executable, but it still contains known contents,
2305 which could be used in certain rare security vulnerability
2306 exploits. This configuration is recommended when userspace
2307 still uses the vsyscall area.
2308
2309 config LEGACY_VSYSCALL_NONE
2310 bool "None"
2311 help
2312 There will be no vsyscall mapping at all. This will
2313 eliminate any risk of ASLR bypass due to the vsyscall
2314 fixed address mapping. Attempts to use the vsyscalls
2315 will be reported to dmesg, so that either old or
2316 malicious userspace programs can be identified.
2317
2318endchoice
2319
2320config CMDLINE_BOOL
2321 bool "Built-in kernel command line"
2322 ---help---
2323 Allow for specifying boot arguments to the kernel at
2324 build time. On some systems (e.g. embedded ones), it is
2325 necessary or convenient to provide some or all of the
2326 kernel boot arguments with the kernel itself (that is,
2327 to not rely on the boot loader to provide them.)
2328
2329 To compile command line arguments into the kernel,
2330 set this option to 'Y', then fill in the
2331 boot arguments in CONFIG_CMDLINE.
2332
2333 Systems with fully functional boot loaders (i.e. non-embedded)
2334 should leave this option set to 'N'.
2335
2336config CMDLINE
2337 string "Built-in kernel command string"
2338 depends on CMDLINE_BOOL
2339 default ""
2340 ---help---
2341 Enter arguments here that should be compiled into the kernel
2342 image and used at boot time. If the boot loader provides a
2343 command line at boot time, it is appended to this string to
2344 form the full kernel command line, when the system boots.
2345
2346 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2347 change this behavior.
2348
2349 In most cases, the command line (whether built-in or provided
2350 by the boot loader) should specify the device for the root
2351 file system.
2352
2353config CMDLINE_OVERRIDE
2354 bool "Built-in command line overrides boot loader arguments"
2355 depends on CMDLINE_BOOL
2356 ---help---
2357 Set this option to 'Y' to have the kernel ignore the boot loader
2358 command line, and use ONLY the built-in command line.
2359
2360 This is used to work around broken boot loaders. This should
2361 be set to 'N' under normal conditions.
2362
2363config MODIFY_LDT_SYSCALL
2364 bool "Enable the LDT (local descriptor table)" if EXPERT
2365 default y
2366 ---help---
2367 Linux can allow user programs to install a per-process x86
2368 Local Descriptor Table (LDT) using the modify_ldt(2) system
2369 call. This is required to run 16-bit or segmented code such as
2370 DOSEMU or some Wine programs. It is also used by some very old
2371 threading libraries.
2372
2373 Enabling this feature adds a small amount of overhead to
2374 context switches and increases the low-level kernel attack
2375 surface. Disabling it removes the modify_ldt(2) system call.
2376
2377 Saying 'N' here may make sense for embedded or server kernels.
2378
2379source "kernel/livepatch/Kconfig"
2380
2381endmenu
2382
2383config ARCH_HAS_ADD_PAGES
2384 def_bool y
2385 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2386
2387config ARCH_ENABLE_MEMORY_HOTPLUG
2388 def_bool y
2389 depends on X86_64 || (X86_32 && HIGHMEM)
2390
2391config ARCH_ENABLE_MEMORY_HOTREMOVE
2392 def_bool y
2393 depends on MEMORY_HOTPLUG
2394
2395config USE_PERCPU_NUMA_NODE_ID
2396 def_bool y
2397 depends on NUMA
2398
2399config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2400 def_bool y
2401 depends on X86_64 || X86_PAE
2402
2403config ARCH_ENABLE_HUGEPAGE_MIGRATION
2404 def_bool y
2405 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2406
2407config ARCH_ENABLE_THP_MIGRATION
2408 def_bool y
2409 depends on X86_64 && TRANSPARENT_HUGEPAGE
2410
2411menu "Power management and ACPI options"
2412
2413config ARCH_HIBERNATION_HEADER
2414 def_bool y
2415 depends on X86_64 && HIBERNATION
2416
2417source "kernel/power/Kconfig"
2418
2419source "drivers/acpi/Kconfig"
2420
2421source "drivers/sfi/Kconfig"
2422
2423config X86_APM_BOOT
2424 def_bool y
2425 depends on APM
2426
2427menuconfig APM
2428 tristate "APM (Advanced Power Management) BIOS support"
2429 depends on X86_32 && PM_SLEEP
2430 ---help---
2431 APM is a BIOS specification for saving power using several different
2432 techniques. This is mostly useful for battery powered laptops with
2433 APM compliant BIOSes. If you say Y here, the system time will be
2434 reset after a RESUME operation, the /proc/apm device will provide
2435 battery status information, and user-space programs will receive
2436 notification of APM "events" (e.g. battery status change).
2437
2438 If you select "Y" here, you can disable actual use of the APM
2439 BIOS by passing the "apm=off" option to the kernel at boot time.
2440
2441 Note that the APM support is almost completely disabled for
2442 machines with more than one CPU.
2443
2444 In order to use APM, you will need supporting software. For location
2445 and more information, read <file:Documentation/power/apm-acpi.txt>
2446 and the Battery Powered Linux mini-HOWTO, available from
2447 <http://www.tldp.org/docs.html#howto>.
2448
2449 This driver does not spin down disk drives (see the hdparm(8)
2450 manpage ("man 8 hdparm") for that), and it doesn't turn off
2451 VESA-compliant "green" monitors.
2452
2453 This driver does not support the TI 4000M TravelMate and the ACER
2454 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2455 desktop machines also don't have compliant BIOSes, and this driver
2456 may cause those machines to panic during the boot phase.
2457
2458 Generally, if you don't have a battery in your machine, there isn't
2459 much point in using this driver and you should say N. If you get
2460 random kernel OOPSes or reboots that don't seem to be related to
2461 anything, try disabling/enabling this option (or disabling/enabling
2462 APM in your BIOS).
2463
2464 Some other things you should try when experiencing seemingly random,
2465 "weird" problems:
2466
2467 1) make sure that you have enough swap space and that it is
2468 enabled.
2469 2) pass the "no-hlt" option to the kernel
2470 3) switch on floating point emulation in the kernel and pass
2471 the "no387" option to the kernel
2472 4) pass the "floppy=nodma" option to the kernel
2473 5) pass the "mem=4M" option to the kernel (thereby disabling
2474 all but the first 4 MB of RAM)
2475 6) make sure that the CPU is not over clocked.
2476 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2477 8) disable the cache from your BIOS settings
2478 9) install a fan for the video card or exchange video RAM
2479 10) install a better fan for the CPU
2480 11) exchange RAM chips
2481 12) exchange the motherboard.
2482
2483 To compile this driver as a module, choose M here: the
2484 module will be called apm.
2485
2486if APM
2487
2488config APM_IGNORE_USER_SUSPEND
2489 bool "Ignore USER SUSPEND"
2490 ---help---
2491 This option will ignore USER SUSPEND requests. On machines with a
2492 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2493 series notebooks, it is necessary to say Y because of a BIOS bug.
2494
2495config APM_DO_ENABLE
2496 bool "Enable PM at boot time"
2497 ---help---
2498 Enable APM features at boot time. From page 36 of the APM BIOS
2499 specification: "When disabled, the APM BIOS does not automatically
2500 power manage devices, enter the Standby State, enter the Suspend
2501 State, or take power saving steps in response to CPU Idle calls."
2502 This driver will make CPU Idle calls when Linux is idle (unless this
2503 feature is turned off -- see "Do CPU IDLE calls", below). This
2504 should always save battery power, but more complicated APM features
2505 will be dependent on your BIOS implementation. You may need to turn
2506 this option off if your computer hangs at boot time when using APM
2507 support, or if it beeps continuously instead of suspending. Turn
2508 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2509 T400CDT. This is off by default since most machines do fine without
2510 this feature.
2511
2512config APM_CPU_IDLE
2513 depends on CPU_IDLE
2514 bool "Make CPU Idle calls when idle"
2515 ---help---
2516 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2517 On some machines, this can activate improved power savings, such as
2518 a slowed CPU clock rate, when the machine is idle. These idle calls
2519 are made after the idle loop has run for some length of time (e.g.,
2520 333 mS). On some machines, this will cause a hang at boot time or
2521 whenever the CPU becomes idle. (On machines with more than one CPU,
2522 this option does nothing.)
2523
2524config APM_DISPLAY_BLANK
2525 bool "Enable console blanking using APM"
2526 ---help---
2527 Enable console blanking using the APM. Some laptops can use this to
2528 turn off the LCD backlight when the screen blanker of the Linux
2529 virtual console blanks the screen. Note that this is only used by
2530 the virtual console screen blanker, and won't turn off the backlight
2531 when using the X Window system. This also doesn't have anything to
2532 do with your VESA-compliant power-saving monitor. Further, this
2533 option doesn't work for all laptops -- it might not turn off your
2534 backlight at all, or it might print a lot of errors to the console,
2535 especially if you are using gpm.
2536
2537config APM_ALLOW_INTS
2538 bool "Allow interrupts during APM BIOS calls"
2539 ---help---
2540 Normally we disable external interrupts while we are making calls to
2541 the APM BIOS as a measure to lessen the effects of a badly behaving
2542 BIOS implementation. The BIOS should reenable interrupts if it
2543 needs to. Unfortunately, some BIOSes do not -- especially those in
2544 many of the newer IBM Thinkpads. If you experience hangs when you
2545 suspend, try setting this to Y. Otherwise, say N.
2546
2547endif # APM
2548
2549source "drivers/cpufreq/Kconfig"
2550
2551source "drivers/cpuidle/Kconfig"
2552
2553source "drivers/idle/Kconfig"
2554
2555endmenu
2556
2557
2558menu "Bus options (PCI etc.)"
2559
2560config PCI
2561 bool "PCI support"
2562 default y
2563 ---help---
2564 Find out whether you have a PCI motherboard. PCI is the name of a
2565 bus system, i.e. the way the CPU talks to the other stuff inside
2566 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2567 VESA. If you have PCI, say Y, otherwise N.
2568
2569choice
2570 prompt "PCI access mode"
2571 depends on X86_32 && PCI
2572 default PCI_GOANY
2573 ---help---
2574 On PCI systems, the BIOS can be used to detect the PCI devices and
2575 determine their configuration. However, some old PCI motherboards
2576 have BIOS bugs and may crash if this is done. Also, some embedded
2577 PCI-based systems don't have any BIOS at all. Linux can also try to
2578 detect the PCI hardware directly without using the BIOS.
2579
2580 With this option, you can specify how Linux should detect the
2581 PCI devices. If you choose "BIOS", the BIOS will be used,
2582 if you choose "Direct", the BIOS won't be used, and if you
2583 choose "MMConfig", then PCI Express MMCONFIG will be used.
2584 If you choose "Any", the kernel will try MMCONFIG, then the
2585 direct access method and falls back to the BIOS if that doesn't
2586 work. If unsure, go with the default, which is "Any".
2587
2588config PCI_GOBIOS
2589 bool "BIOS"
2590
2591config PCI_GOMMCONFIG
2592 bool "MMConfig"
2593
2594config PCI_GODIRECT
2595 bool "Direct"
2596
2597config PCI_GOOLPC
2598 bool "OLPC XO-1"
2599 depends on OLPC
2600
2601config PCI_GOANY
2602 bool "Any"
2603
2604endchoice
2605
2606config PCI_BIOS
2607 def_bool y
2608 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2609
2610# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2611config PCI_DIRECT
2612 def_bool y
2613 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2614
2615config PCI_MMCONFIG
2616 bool "Support mmconfig PCI config space access" if X86_64
2617 default y
2618 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2619 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2620
2621config PCI_OLPC
2622 def_bool y
2623 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2624
2625config PCI_XEN
2626 def_bool y
2627 depends on PCI && XEN
2628 select SWIOTLB_XEN
2629
2630config PCI_DOMAINS
2631 def_bool y
2632 depends on PCI
2633
2634config MMCONF_FAM10H
2635 def_bool y
2636 depends on X86_64 && PCI_MMCONFIG && ACPI
2637
2638config PCI_CNB20LE_QUIRK
2639 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2640 depends on PCI
2641 help
2642 Read the PCI windows out of the CNB20LE host bridge. This allows
2643 PCI hotplug to work on systems with the CNB20LE chipset which do
2644 not have ACPI.
2645
2646 There's no public spec for this chipset, and this functionality
2647 is known to be incomplete.
2648
2649 You should say N unless you know you need this.
2650
2651source "drivers/pci/Kconfig"
2652
2653config ISA_BUS
2654 bool "ISA bus support on modern systems" if EXPERT
2655 help
2656 Expose ISA bus device drivers and options available for selection and
2657 configuration. Enable this option if your target machine has an ISA
2658 bus. ISA is an older system, displaced by PCI and newer bus
2659 architectures -- if your target machine is modern, it probably does
2660 not have an ISA bus.
2661
2662 If unsure, say N.
2663
2664# x86_64 have no ISA slots, but can have ISA-style DMA.
2665config ISA_DMA_API
2666 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2667 default y
2668 help
2669 Enables ISA-style DMA support for devices requiring such controllers.
2670 If unsure, say Y.
2671
2672if X86_32
2673
2674config ISA
2675 bool "ISA support"
2676 ---help---
2677 Find out whether you have ISA slots on your motherboard. ISA is the
2678 name of a bus system, i.e. the way the CPU talks to the other stuff
2679 inside your box. Other bus systems are PCI, EISA, MicroChannel
2680 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2681 newer boards don't support it. If you have ISA, say Y, otherwise N.
2682
2683config EISA
2684 bool "EISA support"
2685 depends on ISA
2686 ---help---
2687 The Extended Industry Standard Architecture (EISA) bus was
2688 developed as an open alternative to the IBM MicroChannel bus.
2689
2690 The EISA bus provided some of the features of the IBM MicroChannel
2691 bus while maintaining backward compatibility with cards made for
2692 the older ISA bus. The EISA bus saw limited use between 1988 and
2693 1995 when it was made obsolete by the PCI bus.
2694
2695 Say Y here if you are building a kernel for an EISA-based machine.
2696
2697 Otherwise, say N.
2698
2699source "drivers/eisa/Kconfig"
2700
2701config SCx200
2702 tristate "NatSemi SCx200 support"
2703 ---help---
2704 This provides basic support for National Semiconductor's
2705 (now AMD's) Geode processors. The driver probes for the
2706 PCI-IDs of several on-chip devices, so its a good dependency
2707 for other scx200_* drivers.
2708
2709 If compiled as a module, the driver is named scx200.
2710
2711config SCx200HR_TIMER
2712 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2713 depends on SCx200
2714 default y
2715 ---help---
2716 This driver provides a clocksource built upon the on-chip
2717 27MHz high-resolution timer. Its also a workaround for
2718 NSC Geode SC-1100's buggy TSC, which loses time when the
2719 processor goes idle (as is done by the scheduler). The
2720 other workaround is idle=poll boot option.
2721
2722config OLPC
2723 bool "One Laptop Per Child support"
2724 depends on !X86_PAE
2725 select GPIOLIB
2726 select OF
2727 select OF_PROMTREE
2728 select IRQ_DOMAIN
2729 ---help---
2730 Add support for detecting the unique features of the OLPC
2731 XO hardware.
2732
2733config OLPC_XO1_PM
2734 bool "OLPC XO-1 Power Management"
2735 depends on OLPC && MFD_CS5535 && PM_SLEEP
2736 select MFD_CORE
2737 ---help---
2738 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2739
2740config OLPC_XO1_RTC
2741 bool "OLPC XO-1 Real Time Clock"
2742 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2743 ---help---
2744 Add support for the XO-1 real time clock, which can be used as a
2745 programmable wakeup source.
2746
2747config OLPC_XO1_SCI
2748 bool "OLPC XO-1 SCI extras"
2749 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2750 depends on INPUT=y
2751 select POWER_SUPPLY
2752 ---help---
2753 Add support for SCI-based features of the OLPC XO-1 laptop:
2754 - EC-driven system wakeups
2755 - Power button
2756 - Ebook switch
2757 - Lid switch
2758 - AC adapter status updates
2759 - Battery status updates
2760
2761config OLPC_XO15_SCI
2762 bool "OLPC XO-1.5 SCI extras"
2763 depends on OLPC && ACPI
2764 select POWER_SUPPLY
2765 ---help---
2766 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2767 - EC-driven system wakeups
2768 - AC adapter status updates
2769 - Battery status updates
2770
2771config ALIX
2772 bool "PCEngines ALIX System Support (LED setup)"
2773 select GPIOLIB
2774 ---help---
2775 This option enables system support for the PCEngines ALIX.
2776 At present this just sets up LEDs for GPIO control on
2777 ALIX2/3/6 boards. However, other system specific setup should
2778 get added here.
2779
2780 Note: You must still enable the drivers for GPIO and LED support
2781 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2782
2783 Note: You have to set alix.force=1 for boards with Award BIOS.
2784
2785config NET5501
2786 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2787 select GPIOLIB
2788 ---help---
2789 This option enables system support for the Soekris Engineering net5501.
2790
2791config GEOS
2792 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2793 select GPIOLIB
2794 depends on DMI
2795 ---help---
2796 This option enables system support for the Traverse Technologies GEOS.
2797
2798config TS5500
2799 bool "Technologic Systems TS-5500 platform support"
2800 depends on MELAN
2801 select CHECK_SIGNATURE
2802 select NEW_LEDS
2803 select LEDS_CLASS
2804 ---help---
2805 This option enables system support for the Technologic Systems TS-5500.
2806
2807endif # X86_32
2808
2809config AMD_NB
2810 def_bool y
2811 depends on CPU_SUP_AMD && PCI
2812
2813source "drivers/pcmcia/Kconfig"
2814
2815config RAPIDIO
2816 tristate "RapidIO support"
2817 depends on PCI
2818 default n
2819 help
2820 If enabled this option will include drivers and the core
2821 infrastructure code to support RapidIO interconnect devices.
2822
2823source "drivers/rapidio/Kconfig"
2824
2825config X86_SYSFB
2826 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2827 help
2828 Firmwares often provide initial graphics framebuffers so the BIOS,
2829 bootloader or kernel can show basic video-output during boot for
2830 user-guidance and debugging. Historically, x86 used the VESA BIOS
2831 Extensions and EFI-framebuffers for this, which are mostly limited
2832 to x86.
2833 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2834 framebuffers so the new generic system-framebuffer drivers can be
2835 used on x86. If the framebuffer is not compatible with the generic
2836 modes, it is advertised as fallback platform framebuffer so legacy
2837 drivers like efifb, vesafb and uvesafb can pick it up.
2838 If this option is not selected, all system framebuffers are always
2839 marked as fallback platform framebuffers as usual.
2840
2841 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2842 not be able to pick up generic system framebuffers if this option
2843 is selected. You are highly encouraged to enable simplefb as
2844 replacement if you select this option. simplefb can correctly deal
2845 with generic system framebuffers. But you should still keep vesafb
2846 and others enabled as fallback if a system framebuffer is
2847 incompatible with simplefb.
2848
2849 If unsure, say Y.
2850
2851endmenu
2852
2853
2854menu "Binary Emulations"
2855
2856config IA32_EMULATION
2857 bool "IA32 Emulation"
2858 depends on X86_64
2859 select ARCH_WANT_OLD_COMPAT_IPC
2860 select BINFMT_ELF
2861 select COMPAT_BINFMT_ELF
2862 select COMPAT_OLD_SIGACTION
2863 ---help---
2864 Include code to run legacy 32-bit programs under a
2865 64-bit kernel. You should likely turn this on, unless you're
2866 100% sure that you don't have any 32-bit programs left.
2867
2868config IA32_AOUT
2869 tristate "IA32 a.out support"
2870 depends on IA32_EMULATION
2871 ---help---
2872 Support old a.out binaries in the 32bit emulation.
2873
2874config X86_X32
2875 bool "x32 ABI for 64-bit mode"
2876 depends on X86_64
2877 ---help---
2878 Include code to run binaries for the x32 native 32-bit ABI
2879 for 64-bit processors. An x32 process gets access to the
2880 full 64-bit register file and wide data path while leaving
2881 pointers at 32 bits for smaller memory footprint.
2882
2883 You will need a recent binutils (2.22 or later) with
2884 elf32_x86_64 support enabled to compile a kernel with this
2885 option set.
2886
2887config COMPAT_32
2888 def_bool y
2889 depends on IA32_EMULATION || X86_32
2890 select HAVE_UID16
2891 select OLD_SIGSUSPEND3
2892
2893config COMPAT
2894 def_bool y
2895 depends on IA32_EMULATION || X86_X32
2896
2897if COMPAT
2898config COMPAT_FOR_U64_ALIGNMENT
2899 def_bool y
2900
2901config SYSVIPC_COMPAT
2902 def_bool y
2903 depends on SYSVIPC
2904endif
2905
2906endmenu
2907
2908
2909config HAVE_ATOMIC_IOMAP
2910 def_bool y
2911 depends on X86_32
2912
2913config X86_DEV_DMA_OPS
2914 bool
2915 depends on X86_64 || STA2X11
2916
2917config X86_DMA_REMAP
2918 bool
2919 depends on STA2X11
2920
2921config HAVE_GENERIC_GUP
2922 def_bool y
2923
2924source "drivers/firmware/Kconfig"
2925
2926source "arch/x86/kvm/Kconfig"